Process for producing c3 chlorinated alkane and alkene compounds

ABSTRACT

A process for producing a reaction mixture comprising a plurality of C 3  chlorinated alkane isomers comprising chlorinating a C 3  chlorinated alkane starting material in a chlorination zone to produce the plurality of C 3  chlorinated alkane isomers, the plurality of C 3  chlorinated alkane isomers each having at least one more chlorine atom than the C 3  chlorinated alkane starting material, wherein the concentration of the C 3  chlorinated alkane starting material is controlled such that conversion of the C 3  chlorinated alkane starting material to the plurality of C 3  chlorinated alkane isomers, represented by the molar ratio of the C 3  chlorinated alkane starting material:C 3  chlorinated alkane isomers in the reaction mixture present in the chlorination zone, does not exceed about 40:60.

This application claims the benefit of Czech Republic Patent ApplicationPV 2015-558, filed Aug. 19, 2015 and Czech Republic Patent ApplicationPV 2015-858, filed Dec. 3, 2015, both of which are incorporated byreference.

The present invention relates to processes for producing very highpurity C₃ chlorinated alkane and alkene compounds which may be used, forexample, as feedstocks for the production of new generationfluorochemicals. The invention also relates to compositions obtainedfrom such processes and the use of those compositions in the preparationof fluorochemicals.

Haloalkanes find utility in a range of applications. For example,halocarbons are used extensively as refrigerants, blowing agents andfoaming agents. Throughout the second half of the twentieth century, theuse of chlorofluoroalkanes increased exponentially until the 1980's,when concerns were raised about their environmental impact, specificallyregarding depletion of the ozone layer.

Subsequently, fluorinated hydrocarbons such as perfluorocarbons andhydrofluorocarbons have been used in place of chlorofluoroalkanes,although more recently, environmental concerns about the use of thatclass of compounds have been raised and legislation has been enacted inthe EU and elsewhere to reduce their use.

New classes of environmentally friendly halocarbons are emerging andhave been investigated, for example, those having low ozonedepletion/global warming potential, and already in some cases, areembraced in a number of applications, especially as refrigerants in theautomotive and domestic fields. Examples of such compounds include2-chloro-3,3,3-trifluoropropene (HFO-1233xf), 1,3,3,3-tetrafluoropropene(HFO-1234ze), 3,3,3-trifluoropropene (HFO-1243zf),2,3,3,3-tetrafluropropene (HFO-1234yf), 1,2,3,3,3-pentafluoropropene(HFO-1225ye), 1-chloro-3,3,3-trifluoropropene (HFO-1233zd),3,3,4,4,4-pentafluorobutene (HFO-1345zf), 1,1,1,4,4,4-hexafluorobutene(HFO-1336mzz), 3,3,4,4,5,5,5-heptafluoropentene (HFO-1447fz),2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy) and1,1,1,4,4,5,5,5-octafluoropentene (HFO-1438mzz). As those skilled in theart will recognize that ‘HFO’ is an abbreviation for hydrofluoroolefin,i.e. an unsaturated compound comprising carbon, hydrogen and fluorineatoms.

Unless otherwise stated, structures depicted herein are also meant toinclude all isomeric forms of the structure, for example (Z) and (E) (orcis or trans) double bond isomers, and (Z) and (E) (or cis or trans)conformational isomers.

While these compounds are, relatively speaking, chemically non-complex,their synthesis on an industrial scale to the required levels of purityis challenging. Many synthetic routes proposed for such compoundsincreasingly use, as starting materials or intermediates, chlorinatedalkanes or alkenes. Examples of such processes are disclosed inWO2012/098420, WO2013/015068 and US2014/171698. The conversion of thechlorinated alkane or alkene starting materials to the fluorinatedtarget compounds is usually achieved using hydrogen fluoride andoptionally transition metal catalysts, for example chromium-basedcatalysts.

An example of an optionally non-catalytic process for preparingfluoroalkenes is disclosed in WO2013/074324.

Examples of processes known to those skilled in the art for preparingseveral of the HFO compounds listed above, starting from a C₃chlorinated alkane/alkene feedstock include:

-   -   1,1,1,2,3-pentachloropropane (HCC-240db) to        2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf);    -   1,1,2,2,3-pentachloropropane (HCC-240aa) to        2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf);    -   1,1,1,2,3-pentachloropropane (HCC-240db) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf);    -   1,1,2,2,3-pentachloropropane (HCC-240aa) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf);    -   1,1,2,3-tetrachloro-1-propene (HCO-1230xa) to        2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf);    -   1,1,2,3-tetrachloro-1-propene (HCO-1230xa) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf)    -   1,1,3,3-tetrachloro-1-propene (HCO-1230za) to        1,1,1-trifluoro-3-chloro-1-propene (HFCO-1233zd),        1,1,1,3-tetrafluoro-1-propene (HFO-1234ze),        1,1,1,3,3-pentafluoropropane (HFC-245fa) and mixtures thereof    -   2,3,3,3-tetrachloro-1-propene (HCO-1230xf) to        2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf).    -   2,3,3,3-tetrachloro-1-propene (HCO-1230xf) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf);    -   2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf);    -   2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db) to        2-chloro-3,3,3-trifluoro-1-propene (HFCO-1233xf);    -   2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db) to        2,3,3,3-tetrafluoro-1-propene (HFO-1234yf).

The issue of the formation of impurities during hydrofluorinationreactions is known and is of concern especially given that certainimpurities can impede continuous hydrofluorination on an industrialscale and/or result in the formation of unwanted fluorinated compoundswhich are difficult to remove from the final target HFO compounds. Thoseunwanted HFO compounds not only render the target HFO compound/s impure,but also may have toxic effects and/or interfere with the desiredoperation of the target HFO in its intended application, for example asblowing agents or heat transfer fluids, e.g. refrigerants.

Attempts to prevent or retard the formation of unwanted impurities inHFO production are disclosed in the prior art. For example,US2010/331583 and WO2013/119919 describe the need for purity in the partfluorinated feedstock (as well as approaches for improving purity).Additionally, U.S. Pat. No. 8,252,964 describes use of molecular sievesto remove impurities from HFO compounds. WO2013/184865 advocates the useof further reactions to separate out difficult to remove impurities fromHFO compounds of interest. US2014/235903 addresses the problem ofreactor impurities.

The purity of the chlorinated starting materials will have a substantialeffect on the success and viability of the processes (especiallycontinuous processes) for preparing the desirable fluorinated products.The presence of certain impurities will result in side reactions,minimising the yield of the target compound. Impurities in thechlorinated feedstock will also be transformed into fluorinatedimpurities in the HFO compound of interest. Removal of these impuritiesthrough the use of distillation steps is also challenging and/orinefficient. Additionally, the presence of certain impurities willcompromise catalyst life, by, for example, acting as catalyst poisons.

A variety of impurities can exist in the chlorinated feedstock, e.g.oxygenated compounds, chlorinated alkanes other than the compound ofinterest, under chlorinated compounds (i.e. compounds comprising fewerchlorine atoms than the compound of interest), over chlorinatedcompounds (i.e. compounds comprising more chlorine atoms than thecompound of interest), isomers of the target compound, and/or residuesof any catalysts used.

It has been recognised that when the chlorinated feedstock is itselfobtained from a multi-step process, especially if such steps are linkedand run continuously to achieve industrially acceptable product volumes,then the need to prevent cumulative side reactions from generatingunacceptable impurities at each process step is very important. This isimportant for C₃ chlorinated compounds, as conventional processes forproducing such compounds are often affected by the formation of a rangeof side products. Accordingly, it is generally desirable to streamlineprocesses for producing such compounds so that fewer steps are involved.Examples of attempts to improve the efficiency of processes forpreparing C₃ chlorinated compounds are disclosed in U.S. Pat. No.8,907,147, which describes the use of reactive distillation processeswhich combine two reactions in one reactor system and WO2014/116562,which describes the direct production of 240db, by chlorination of 250fbusing antimony based catalysts.

Accordingly, there is a need for C₃ chlorinated alkanes and alkeneshaving controlled and acceptable impurity profiles for use in thesynthesis of the fluorinated compounds mentioned above. Severalprocesses for producing purified chlorinated compounds have beenproposed in the art.

For example, WO2013/086262 discloses a process for preparing1,1,2,2,3-pentachloropropane from methylacetylene gas. As can be seenfrom the examples in that application, the bench scale synthesesdisclosed therein resulted in a product having around 98.5% purity,despite being subjected to post-synthetic purification process,specifically distillation.

In WO2014/130445, a conventional process is discussed on page 2 of thatpublication, the first step of which involves the formation of1,1,1,2,3-pentachloropropane from 1,1,3-trichloropropene. However, thepurity profile of that intermediate product is not outlined, nor is anyimportance attached to the purity profile of that product. In Example 2of WO2014/130445, a 240db (1,1,1,2,3-pentachloropropane) rich materialhaving a purity level of 96.5 to 98.5% is used.

WO2013/055894 discloses a process for producing tetrachloropropenes,particularly 1,1,2,3-tetrachloropropene and reports that the productobtained from the processes disclosed in that document haveadvantageously low levels of impurities which can be problematic indownstream processes for producing fluorocarbons. A discussion of thedifferent types of impurities considered to be problematic by theauthors of WO2013/055894 is set out in paragraphs [0016] and [0017] ofthat document.

US2012/157723 discloses a process for preparing chlorinated alkanes viaa three step process. Seemingly high purity chloroalkanes appear to havebeen prepared according to the process disclosed in that document.However, the efficiency of the processes is not addressed and the puritydata presented in the examples of that application are only given to onedecimal place.

From the provision of data presented in this way, it is apparent thatthe analytical equipment used to measure the impurity profile of theproducts obtained in the examples of US2012/157723 was insensitive;conventional analytical apparatus enables hydrocarbon levels to 1 ppm(i.e. to four decimal places) to be determined. Given that one skilledin the art would need to know the impurity profile of chloroalkanefeedstocks to be used in industrial scale down to a ppm level, the datapresented in US2012/157723 would not be of assistance.

Despite these advances, problems can still arise through the use ofchlorinated compounds obtained from the processes discussed above.Particularly, the presence of impurities, especially those which are noteasily separable from the compounds of interest (e.g. as a result ofsimilar or higher boiling points), which lead to the formation ofside-products during storage, transportation, and/or use in downstreamprocesses such as hydrofluorination, and/or which reduce theeffectiveness or operating life of catalysts used in downstreamprocesses can be problematic.

International applications Nos. WO2016/058566, WO2016/058567 andWO2016/058568 (the contents of which are incorporated herein byreference) describe processes for preparing compositions comprising C₃₋₆chlorinated alkanes and alkenes having very high levels of purity inhigh yields, with minimal loss to side products.

A demand remains for very high purity chlorinated alkane and alkenecompounds, and also for efficient, selective and reliable processes forpreparing such compounds, especially enabling continuous industrialmanufacture.

Demand also remains for additional processes for preparing very highpurity chlorinated alkane and alkene compounds including in continuousmode, which have very low levels or are ideally free of impurities whichare known or are thought to be problematic in downstream processes.

Thus, according to a first aspect of the present invention, there isprovided a process for producing a reaction mixture comprising aplurality of C₃ chlorinated alkane isomers comprising chlorinating a C₃chlorinated alkane starting material in a chlorination zone to producethe plurality of C₃ chlorinated alkane isomers, the plurality of C₃chlorinated alkane isomers each having at least one more chlorine atomthan the C₃ chlorinated alkane starting material, wherein theconcentration of the C₃ chlorinated alkane starting material iscontrolled such that conversion of the C₃ chlorinated alkane to theplurality of C₃ chlorinated alkane isomers, represented by the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers in the reaction mixture present in the chlorination zonedoes not exceed about 40:60.

The process of this aspect of the present invention advantageouslyenables the production of a reaction mixture comprising a plurality oftarget C₃ chlorinated alkane isomers which (excluding starting materialsand catalyst) preferably has a purity (i.e. content of the plurality ofC₃ chlorinated alkane isomers) of about 98% or higher, about 98.5%,about 99%, about 99.5% or higher, about 99.7% or higher or about 99.9%or higher by weight.

For the avoidance of doubt, where the purity of a composition ormaterial (including the plurality of C₃ chlorinated alkane isomers) ispresented by percentage or ppm, unless otherwise stated, this is apercentage/ppm by weight.

It has been found by the inventors that it is essential to control thechlorination of the C₃ chlorinated alkane starting material such thatthe molar ratio of that starting material:plurality of isomers does notexceed about 40:60 in order to minimise the formation of problematicside products/impurities enabling the production of high grade products,even when the processes are operated in continuous mode.

The focus of many processes of the prior art is to produce compositionscomprising single isomers in high purity, especially given that C₃chlorinated alkane isomers are typically difficult to separate out usingconventional techniques. However, it has been found by the inventorsthat the high purity mixtures of isomers of such compounds can be viablyemployed in downstream processes such as hydrofluorination,dehydrochlorination and/or isomerisation processes. Advantageously, theprocesses of the present invention can be operated continuously,efficiently and in a streamline manner to produce compounds having highpurity levels.

For example, a plurality of chlorinated alkane isomers can viably beemployed as a feedstock in the preparation of refrigerants or blowingagent components such as 1234yf, 1234zeE and/or 1233zdE.Refrigerant/blowing agent compositions comprising these components athigh levels of purity are of commercial value and thus, there issignificant interest in processes which can be used to reliably andefficiently provide highly pure chlorinated compounds that can be usedas feedstocks to produce such compounds. The processes of this aspect ofthe present invention can be employed to produce two or more keyfeedstocks from a single production line.

Additionally or alternatively, the processes of the present inventioncan be used to efficiently produce high purity commercially valuable C₃chlorinated compounds including 1,1,1,3,3-pentachloropropane(HCC-240fa), 1,1,3,3-tetrachloro-1-propene (HCO-1230za),1,1,1,2,3-pentachloropropane (HCC-240db), 1,1,2,3-tetrachloro-1-propene(HCO-1230xa), 1,3,3,3-tetrachloro-1-propene (HCO-1230zd), and mixturesthereof, such as those disclosed in US2014/0221704.

One key advantage of the chlorinated alkane materials which may beobtained from the processes of the present invention is that their highpurity enables them to be handled safely and with ease as the absence oracceptably low levels of impurities which could otherwise catalysedegradation over time or could interact with storage/transport vesselsproducing other catalysts are not present. Those chlorinated materialsare therefore easier to transport, not requiring specialist measures tobe taken, such as those disclosed in WO2014/120865.

The use of isomeric C₃ chlorinated alkane compounds is also advantageousas it simplifies production. More specifically, the use of suchcompositions enables multiple feedstocks to be prepared (as will bediscussed below) using common upstream starting materials. As anexample, if one skilled in the art wished to produce the commerciallyvaluable chlorinated alkenes 1,1,3,3-tetrachloro-1-propene (HCO-1230za)and 1,1,2,3-tetrachloro-1-propene (HCO-1230xa), they would be aware ofprocesses for preparing these compounds from1,1,1,3,3-pentachloropropane (HCC-240fa) and1,1,1,2,3-pentachloropropane (HCC-240db). However, conventionally,HCC-240fa is produced from vinyl chloride and carbon tetrachloride whileHCC-240db is produced from ethylene, carbon tetrachloride and chlorine.The identification by the present inventors that multiple chlorinatedalkenes can be viably and reliably produced from a single C₃ chlorinatedalkane starting material simplifies the overall production of thosechlorinated alkenes, reduces the number of starting materials andproduction lines, and enables the use of potentially undesirablecompounds such as vinyl chloride (which is known to be highly toxic,unstable and challenging to store/transport) to be avoided. Instead, thepresent invention enables the use of basic starting materials (such asethylene and chlorine) on an industrial scale to obtain the chlorinatedalkenes of interest.

As a result of the advantageous processes of the present invention, theplurality of C₃ chlorinated alkane isomers prepared in processes of thisaspect of the invention have high purity. This means that thosecompounds can be used themselves in downstream reactions with or withoutseparation from each other to produce compounds which also benefit fromdesirable impurity profiles, minimizing the need for downstreampurification steps.

For clarity, the term “plurality of C₃ chlorinated alkane isomers” orthe like, as used herein, is not to be taken in its broadest sense—tomean any mixture in which a plurality of C₃ chlorinated alkane isomersare present in any amount.

Those skilled in the art will consider that a mixture comprising, forexample, two isomers where one of those isomers is only present in traceamounts does not include a ‘plurality’ for the purposes of the presentinvention. Thus, the term “plurality of C₃ chlorinated alkane isomers”,or equivalent language, as used herein, means a group of C₃ chlorinatedalkane isomers comprising at least two or more C₃ chlorinated alkaneisomers each having the same number of chlorine and hydrogen atoms andeach being present in an amount of 1% or more by weight of the totalmixture of those isomers. Further, for the avoidance of doubt, anyisomer present in the mixture in an amount of less than 1% by weight ofthe total amount of the isomers is not considered to be a componentisomer of that plurality, but an impurity (an “isomeric impurity”). Inpreferred embodiments of the present invention, the content of suchisomeric impurity/ies in the reaction mixture produced in thechlorination zone is less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, less than about 100 ppm, less than about 50ppm, less than about 20 ppm, less than about 10 ppm or less than about 5ppm.

Likewise, the reaction mixture preferably comprises low amounts of underchlorinated impurities (i.e. C₃ compound/s having one or more fewerchlorine atoms than the plurality of isomers, not including the C₃starting material) for example, less than about 25000 ppm, less thanabout 20000 ppm, less than about 10000 ppm, less than about 5000 ppm,less than about 2000 ppm, less than about 1000 ppm, less than about 500ppm, less than about 200 ppm, less than about 100 ppm, less than about50 ppm, less than about ppm, less than about 10 ppm or less than about 5ppm

Additionally, the reaction mixture preferably comprises low amounts ofover chlorinated impurities (i.e. C₃ compound/s having one or moreadditional chlorine atoms than the plurality of alkane isomers) forexample, less than about 50000 ppm, less than about 30000 ppm, less thanabout 25000 ppm, less than about 20000 ppm, less than about 15000 ppm,less than about 10000 ppm, less than about 5000 ppm, less than about2000 ppm or less than about 1000 ppm.

Further, the reaction mixture preferably comprises low amounts ofcompounds having a different number of carbon atoms than the isomers forexample, less than about 1000 ppm, less than about 500 ppm, less thanabout 200 ppm, less than about 100 ppm, less than about 50 ppm, lessthan about 20 ppm, less than about 10 ppm or less than about 5 ppm.

Additionally or alternatively, the reaction mixture may comprise lowamounts of chlorinated alkene compounds for example, less than about5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less thanabout 500 ppm, less than about 200 ppm, less than about 100 ppm, lessthan about 50 ppm, less than about 20 ppm, less than about 10 ppm orless than about 5 ppm.

In embodiments of the invention, the plurality of C₃ chlorinated alkaneisomers may comprise any number of component isomers (i.e. isomers beingpresent in an amount of 1% or more by weight of the total plurality ofisomers). For example, the plurality of C₃ chlorinated alkane isomersmay comprise 2, 3, 4, 5, 6, 7, 8, 9 or more component isomers. Inembodiments of the invention, the plurality of the C₃ chlorinated alkaneisomers comprises two isomers, the first isomer and the second isomer.

In embodiments of the invention, the plurality of isomers is typicallyformed with the individual isomers not being present in a balancedratio, i.e. the levels of each isomer will vary, with one isomer beingpresent in a greater amount. Thus, in embodiments where the plurality ofC₃ chlorinated alkane isomers comprises two isomers, one will be presentin a greater amount than the other. In such embodiments, the ratio ofisomers (e.g. the molar ratio of first isomer:second isomer or secondisomer:first isomer produced in the chlorination zone may range fromabout 60:40, about 65:35 or about 70:30 to about 90:10, about 95:5 orabout 98:2). As discussed herein, the processes of the present inventionpermit the ratio of the isomers to be controlled, e.g. by varying themethod of catalysis and/or the type of reactor used. Thus, inalternative embodiments where a more balanced ratio of isomers ispreferred, this can be achieved using processes of the presentinvention. In such embodiments, the molar ratio of first isomer:secondisomer or second isomer:first isomer produced in the chlorination zonemay range from about 40:60 to about 60:40.

The component isomers present in the plurality will each include thesame number of carbon, chlorine and hydrogen atoms. Their boiling pointsmay vary, although, owing to their structural similarity, it isenvisaged that in many cases, the variations in boiling points betweenthe component isomers present in the plurality will be relativelylimited. For example, in embodiments of the invention, the boilingpoints of at least two of the component isomers present in the pluralitywill vary by ≦about 20° C., by ≦about 15° C., by ≦about 10° C. or by≦about 5° C. In additional or alternative embodiments of the invention,the boiling point of the component isomer having the highest boilingpoint of all of the component isomers present in the plurality will be≦about 20° C., ≦about 15° C., ≦about 10° C. or ≦about 5° C. higher thanthe boiling point of the component isomer having the lowest boilingpoint of all of the component isomers present in the plurality.

In embodiments of the invention, one, some or all of the C₃ chlorinatedalkane isomers in the plurality comprises three chlorine atoms on aterminal carbon atom in the molecule.

Examples of pluralities of C₃ chlorinated isomers that may be preparedor employed according to processes of the present invention include i)1,1,1,2,3-pentachloropropane and 1,1,1,3,3-pentachloropropane ii)1,1,1,2,3-pentachloropropane and 1,1,2,2,3-pentachloropropane, and iii)1,1,2,2,3-pentachloropropane and 1,1,1,2,2-pentachloropropane. In theisomeric pairs outlined in this paragraph, the first listed isomer maybe the first isomer or the second isomer, and the second listed isomermay be the other of the first isomer or the second isomer.

Advantageously, in the processes of the present invention, thepreparation of these pluralities of chlorinated alkane isomers is highlyselective. The formation of over-chlorinated or under-chlorinated alkaneimpurities is minimal, as is the formation of pentachloropropane isomersother than the isomers of interest.

In processes of the present invention, for example group i) may beprepared by chlorinating 1,1,1,3-tetrachloropropane. Group ii) may beprepared by chlorinating 1,2,3-trichloropropane,1,2,2,3-tetrachloropropane, 1,1,2,3-tetrachloropropane or a mixture of1,1,2,3-tetrachloropropane and 1,2,2,3-tetrachloropropane. Group iii)may be prepared by chlorinating 1,2-dichloropropane or1,1,2,2-tetrachloropropane and 1,2,2,3-tetrachloropropane. Any of thesecompounds or mixtures thereof may be employed as starting materials inprocesses of the present invention.

A further advantage of the process of the present invention is that theformation of impurities which may be problematic in downstream processesis limited, or ideally prevented. For example, the formation ofimpurities arising from the serial chlorination of compounds present inthe reaction mixture is prevented by controlling the level of C₃chlorinated alkane starting material present in the mixture in thechlorination zone.

Thus, for example, where the chlorinated alkane isomers present in thereaction mixture formed in the chlorination step employed in the processof this aspect of the present invention include one more chlorine atomthan the chlorinated alkane starting material, the production ofcompounds including two or more chlorine atoms than the startingmaterial is restrained.

In such embodiments, the reaction mixture present in the chlorinationzone may comprise less than about 5%, less than about 2%, less thanabout 1%, less than about 0.5%, less than about 0.2%, less than about0.1%, less than about 0.05%, less than about 0.02%, or less than about0.01% of compounds including two or more chlorine atoms than the C₃chlorinated alkane starting material.

The inventors have found that, under certain operating conditions,maintaining the molar ratio of the C₃ chlorinated alkane startingmaterial:C₃ chlorinated alkane isomers obtained by the chlorination ofthe C₃ chlorinated starting material in the reaction mixture present inthe chlorination zone such that it does not exceed 40:60, i.e. theconversion of the C₃ chlorinated alkane starting material to theplurality of isomers is limited to 60%, plays a significant role inpreventing serial chlorination of the starting material which wouldotherwise lead to the formation of highly reactive materials. For theavoidance of doubt, in the present application, where reference is madeto controlling or limiting a molar ratio of starting material:productsuch that it does not exceed a specified level, this means that theconversion of the starting material to the specified product is limitedto the level specified in the given ratio.

In embodiments of the invention, the molar ratio of the C₃ chlorinatedalkane starting material:C₃ chlorinated alkane isomers in the reactionmixture present in the chlorination zone/extracted therefrom may bemaintained in the range of about 99:1, about 97:3, about 95:5 to about90:10, about 85:15 about 80:20 or about 75:25. Alternatively, the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers in the reaction mixture present in the chlorinationzone/extracted therefrom may be maintained in the range of about 90:10,about 80:20, or about 70:30 to about 65:35, about 60:40 or about 55:45.In alternative embodiments, the ratio may be about 90:10, about 80:20,about 70:30, to about 60:40, about 50:50 to about 40:60. Example 8confirms the effect of the degree of conversion of the starting materialto the isomers of interest on the formation of impurities.

As those skilled in the art will appreciate, while control over thechlorination process is characterised herein in terms of the molar ratiobetween starting material and the isomeric product, it can alsoconsidered as control over the conversion of starting material toproduct—thus a molar ratio of starting material:isomeric product of75:25 equates to a conversion of 25%. The inventors have found thatlimiting the conversion of the starting material as outlined aboveminimises the formation of undesirable impurities.

Any technique or equipment may be used by those skilled in the art todetermine the composition of the reaction mixture present in thechlorination zone. For example, a direct determination of the reactionmixture can be made e.g. by providing the chlorination zone with a portthrough which samples of the reaction mixture can be extracted foranalysis. Additionally or alternatively, reaction mixture is extractedfrom the chlorination and subjected to further treatment steps. In suchembodiments, samples of reaction mixture may be taken upon extraction ofthat reaction mixture from the chlorination zone, e.g. via a portlocated at or in the vicinity of the outlet of the chlorination zone.Additionally or alternatively, an indirect determination of thecomposition can be made e.g. by temperature control as temperature is afunction of composition at constant pressure. The determination of thecomposition should be made at the point at which the reaction mixture isextracted from the chlorination zone, or, in embodiments in which the C₃chlorinated alkane isomers are extracted directly from the reactionmixture in the reaction zone at the point at which that extractionoccurs.

The problem of serial chlorination of the starting material is addressedby the processes of the present invention. More specifically,International Patent Application No. WO98/05614 discloses the formationof mixtures of C₃ chlorinated alkane isomers, specifically1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane. However,the inventors, having reproduced the examples of WO98/05614 have foundthat the processes disclosed in that document inevitably result in theformation of hexachloropropanes, especially1,1,1,3,3,3-hexachloropropane. This serial chlorination product has avery close boiling point to 1,1,1,2,3-pentachloropropane (240db) makingits separation from the pentachloropropane of interest challenging.Further, it is very unstable in the presence of metals and thus producesfurther degradation products (such as 1,1,3,3,3-pentachloropropene)during downstream processing steps such as distillation and/or atelevated temperatures.

The present inventors have identified that by limiting the molar ratioof C₃ chlorinated alkane feedstock (e.g. 1,1,1,3-tetrachloropropane) andthe resulting pentachloropropane isomers in the chlorination zone to40:60, the formation of the over chlorinated side products such asunstable 1,1,1,3,3,3-hexachloropropane is minimised.

The level of the chlorinated alkane starting material in the reactionmixture may be controlled by, for example, i) removing the C₃chlorinated alkane isomers (by extracting reaction mixture and/or byextracting a C₃ chlorinated alkane rich stream, e.g. via directdistillation) from the chlorination zone, ii) by controlling thereaction conditions in the chlorination zone (e.g. temperature, exposureto light, catalyst concentration and/or pressure), and/or iii) bycontrolling the amount of chlorinated alkane starting material and/orchlorine present in the chlorination zone.

This list is not exhaustive; any method or technique can be utilised tocontrol the reaction rate, so that the formation of over chlorinatedimpurities and/or serial adducts to higher adduct compounds can beavoided.

In embodiments of the present invention, reaction mixture may beextracted from the chlorination zone and/or subjected to directdistillation (i.e. where distillation apparatus is in directcommunication with the chlorination zone). In such embodiments, owing tocontrol over the conversion of the starting material to the plurality ofisomers, the reaction mixture which is extracted from the chlorinationzone and/or subjected to direct distillation has a molar ratio of the C₃chlorinated alkane starting material:C₃ chlorinated alkane isomers asoutlined above, i.e. which does not exceed 40:60 or which, in certainembodiments may have narrower ranges, again, as outlined above.

The rate of agitation or stirring of the chlorination zone canadditionally or alternatively be reduced to retard the chlorinationprocess.

In embodiments of the invention in which the degree of conversion of thechlorinated alkane starting material to the chlorinated alkane isomersof interest is controlled (i.e. limited) by controlling the amount ofchlorine present in the chlorination zone, the chlorine content in thereaction mixture extracted from the chlorination zone may be very low,for example about 1% or less, about 0.5% or less, about 0.1% or less,about 0.05% or less or about 0.01% or less.

Additionally, or alternatively, to control the degree of conversion ofthe starting material to the isomers of interest, the amount ofmolecular chlorine provided into the chlorination zone maysubstoichiometric as compared to the C₃ chlorinated alkane startingmaterial. For example, the amount of molecular chlorine provided intothe chlorination zone may be about 5%, about 10%, about 15% or about 20%to about 25%, about 30%, about 35%, about 40%, about 50%, about 60%, orabout 70%, of the moles of C₃ chlorinated alkane starting materialprovided to the chlorination zone.

In embodiments of this aspect of the invention, the starting material isa C₃ chlorinated alkane comprising 1, 2, 3, 4, 5 or 6 chlorine atoms. Inthe chlorination step employed in the process of this aspect of thepresent invention, the C₃ chlorinated alkane starting material may beconverted to a plurality of isomers having the same number of carbonatoms as the starting material, and 1, 2, 3 or more chlorine atoms thanthe starting material.

The C₃ chlorinated alkane starting material preferably has a high degreeof purity. For example, the starting material may have a purity of about98% or higher, about 98.5% or higher, about 99% or higher, about 99.5%or higher, about 99.7% or higher, about 99.9% or higher. Processes forpreparing such compositions and such compositions with definedimpurities are disclosed in W2016/058566, the contents of which areincorporated herein by reference.

While C₃ chlorinated alkane starting materials employed in the processof this aspect of the present invention may be obtained from anysynthetic route, it is generally preferred that the starting material isnot obtained from a route employing a chlorinated alkene (e.g. vinylchloride) as a starting material. This is because the C₃ chlorinatedalkane starting material may comprise residual amounts of chlorinatedalkene (e.g. vinyl chloride) which is problematic as chlorinated alkenes(e.g. vinyl chloride) are toxic and may also polymerise to form polymers(e.g. polyvinylchloride) that can cause reactor clogging in downstreamprocesses. Vinyl chloride monomers are also challenging tostore/transport and have safety issues, thus the avoidance of the use ofstarting materials which are free of such monomers is preferable.

Thus, in embodiments of this aspect of the present invention, the C₃chlorinated alkane starting material is obtained from chlorinatedalkene-free (e.g. vinyl chloride-free) processes (i.e. processes notemploying chlorinated alkenes such as vinyl chloride as a reactant)and/or which comprise less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, less than about 100 ppm, less than about 50ppm, less than about ppm, less than about 10 ppm, less than about 5 ppmor less than about 2 ppm chlorinated alkene (e.g. vinyl chloride).

Examples of processes for producing such a starting material aredisclosed in W2016/058566, the contents of which are incorporated hereinby reference. The processes provided in those applications enable highpurity C₃ chlorinated alkanes to be produced.

Such feedstocks, whether produced according to such processes or not,may be employed as starting materials in the processes of the presentinvention and which may comprise:

-   -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm or less than 50 ppm chlorinated alkane impurities (i.e.        chlorinated alkane compounds other than the chlorinated C₃        alkane starting material), e.g. chlorobutane,    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm, or less than about 50 ppm, or less than ppm chlorinated        alkene compounds, e.g. perchloroethylene,    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm or less than about 50 ppm, or less than ppm oxygenated        organic compounds,    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm brominated compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm        or less than about 20 ppm of water,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm or less than about 20 ppm        metallic catalyst, and/or    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm or less than about 20 ppm        catalyst promoter.

Advantageously, in embodiments of the invention, the use of C₃chlorinated alkane starting materials having one trichlorinated terminalcarbon atom minimises the number of chlorinated alkane isomers which areformed. Thus, in embodiments of the invention, the C₃ chlorinated alkanestarting material is a compound having a trichlorinated terminal carbonatom.

In embodiments of the present invention, the C₃ chlorinated alkanestarting material may be 1,1,1,3-tetrachloropropane (which, inembodiments of the invention, may be obtained from carbon tetrachlorideand ethylene), mixture of 1,1,2,3-tetrachloropropane and1,2,2,3-tetrachloropropane (which may be obtained from1,2,3-trichloropropane from 3-chloropropene), 1,1,2,3-tetrachloropropane(which may be obtained from 1,3-dichloropropene), mixture of1,1,2,2-tetrachloropropane and 1,2,2,3-tetrachloropropane (which may beobtained from 1,2,2-trichloropropane from 2-chloropropene or from1,2-dichlorpropane). In embodiments where 1,1,1,3-tetrachloropropane isemployed as the C₃ chlorinated alkane starting material, that materialpreferably comprises levels of per chlorinated ethylene, chlorinatedbutyl compounds and iron residues within the limits outlined above.

In embodiments of this aspect of the present invention, chlorination ofthe C₃ chlorinated alkane starting material may be carried out byreacting the starting material with chlorine. For example, this may beachieved by contacting the chlorine and the C₃ chlorinated alkanestarting material in the chlorination zone by those reactants being fedinto that zone using any technique or equipment known to those skilledin the art, for example via dispersion devices such as tube/s (e.g. diptube/s), nozzle/s, porous plates, ejectors, static mixing devices and/orsparger/s. In such embodiments, the feed of chlorine and/or C₃chlorinated alkane starting material may be continuous or intermittent.The chlorine supplied as a feed into the chlorination zone in which thereaction mixture is present may be in liquid and/or gaseous form.Likewise, the C₃ chlorinated alkane starting material may be in liquidand/or gaseous form. The chlorination zone may be fed with one or morechlorine feeds. Additional vigorous stirring may be used to ensure goodmixing and/or dissolution of the chlorine into the liquid reactionmixture.

Where the reaction mixture in the chlorination zone is liquid, thechlorine may be fed into the chlorination zone as gas into the headspaceof the chlorination zone. Additionally, or alternatively, the chlorinemay be fed into the reaction mixture, a solvent, a process intermediateand/or the feed stream of the C₃ starting material upstream of thechlorination zone and dissolved or entrained therein.

In embodiments of the present invention, the reaction conducted in thechlorination zone is in the liquid phase, i.e., the reaction mixturepresent therein is predominantly or totally liquid. The reaction mixturemay be analysed using any techniques known to those skilled in the arte.g. chromatography.

The chlorine used as a starting material in the processes of the presentinvention is preferably highly pure. In embodiments of the invention,the chlorine preferably has a purity of at least about 95%, at leastabout 97%, at least about 99%, at least about 99.5%, or at least about99.9%

Additionally or alternatively, the chlorine used in the processes of thepresent invention may comprise bromine or bromide in an amount of about200 ppm or less, about 100 ppm or less, about 50 ppm or less, about 20ppm or less or about 10 ppm or less.

The use of chlorine gas comprising low amounts of oxygen (e.g. about 200ppm or less, about 100 ppm or less, about 50 ppm or less, about 20 ppmor less or about 10 ppm or less) is also envisaged. However, inembodiments of the present invention, lower grade chlorine (includinghigher oxygen levels, e.g. of 1000 ppm or higher) can be employedwithout the final product of the processes of the present inventioncomprising unacceptably high levels of oxygenated impurities.

In embodiments of the present invention, chlorine content within thechlorination zone is controlled as this has been found to minimise theformation of side products. In such embodiments, it is preferable if thechlorination zone is equipped with monitoring means to detect chlorinelevels within the chlorination zone and/or at the reactor outlet.

In embodiments of the present invention, chlorination of the C₃chlorinated alkane starting material may be catalyzed. For example,chlorination may be carried out under exposure to UV and/or visiblelight (“photochlorination”). For example, this may be achieved byincluding a UV and/or visible light source in the chlorination zone,e.g. glass tubes for light introduction within the chlorination zone.Additionally or alternatively, a wall in the reactor may be transparentenabling the passage of UV and/or visible light into the chlorinationzone within the reactor. In embodiments, exposure of the reactionmixture to light (for example ultra violet light) promotes the reactionwhen operated at low temperatures.

In embodiments in which photochlorination is carried out, light flux,power and wavelength into the chlorination zone is preferablycontrolled.

Additionally or alternatively, chlorination of the C₃ chlorinated alkanestarting material may be catalyzed by Lewis acid type catalysts such asmetal and/or hybrid metal catalysts. Examples of such catalysts includeone or more halides (e.g. chlorides, bromides, fluorides or iodides) oftransition metals such as iron, aluminium, antimony, lanthanum, tin,titanium, or boron or elements such as sulphur or iodine. Specificexamples of catalysts that may be employed include FeCl₃, AlCl₃, SbCl₅,SnCl₄, TiCl₄, BF₃, SO₂Cl₂ and/or metal triflate. Ferric chloride can bealso prepared in-situ by means of the direct or indirect addition ofiron catalyst precursor (for example solid iron) into the reactionmixture.

Such catalysts, where used, may be employed in any quantity, providedthat effective catalysis of the reaction. However, in embodiments of theinvention, relatively low amounts of catalyst may be used, for example,less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400ppm, less than 300 ppm, less than 200 ppm, less than 150 ppm or lessthan 100 ppm, to more than about 2 ppm, more than about 5 ppm, more thanabout 7 ppm or more than about 10 ppm

The inventors have unexpectedly found that the type of catalysis usedduring chlorination influences the ratio of C₃ chloroalkane isomers thatare produced. Generally speaking, where photochlorination is used in theabsence of other catalysts such as Lewis acid catalysts, this favoursthe formation of a first chlorinated alkane isomer, while if a Lewisacid catalyst is used in combination with UV/visible light, this favoursthe formation of a second chlorinated alkane isomer. In embodiments ofthe present invention, therefore, the chlorination reaction is catalyzed(or promoted) using only UV and/or visible light in order to achieveselectivity in favour of a first isomer over a second isomer of about60%, about 70% or about 75%. In alternative embodiments, a combinationof Lewis acid and UV and/or visible light is used to catalyse thechlorination reaction in order to achieve selectivity in favour of asecond isomer over a first isomer of about 60%, about 70%, about 80%,about 90% or about 95%.

Thus, in embodiments of the present invention, chlorination of the C₃chlorinated alkane starting material is promoted/catalysed by i)exposure to UV/visible light and ii) Lewis acid. In such embodiments,the process additionally comprises the step of controlling i) theduration and/or extent of exposure to, wavelength of, flux of and/orpower of the UV/visible light, and/or ii) the concentration of Lewisacid in the reaction mixture.

As an example of such a system, the inventors have successfullycontrolled the molar ratio of 1,1,1,3,3-pentachloropropane and1,1,1,2,3-pentachloropropane from 80:20 (using only exposure to UVlight), through 70:30, 60:40, 50:50, 40:60, finishing 2:98 (using thecombination of promoted/catalysed chlorination comprising UV and Lewisacid). This approach enables the production of chlorinated alkaneisomers at predetermined ratios and also selectively, such thatnon-target pentachloropane isomers are not formed.

As is demonstrated in the examples that follow, other reactionconditions which influence the molar ratio of isomers formed in theprocesses of the present invention additionally include residence timeof the reaction mixture in the chlorination zone as well as operatingtemperature within the chlorination zone.

Thus, in embodiments of the invention, the mean residence time of thereaction mixture in the chlorination zone may be about 60 minutes orless, about 45 minutes or less, about 30 minutes or less, about 20minutes or less, about 15 minutes or less or about 10 minutes or less.Alternatively, the mean residence time of the reaction mixture in thechlorination zone may be about 60 minutes or more, about 75 minutes ormore, about 90 minutes or more, or about 120 minutes or more. Inembodiments of the invention, the mean residence time of the reactionmixture in the chlorination zone may be from about 10 minutes to about40 minutes, from about 40 minutes to about 80 minutes, or about 80minutes or longer.

Additionally or alternatively, the operating temperature of thechlorination zone may be about 60° C. or less, about 45° C. or less,about 30° C. or less, about 20° C. or less, about 15° C. or less orabout 10° C. or less. Alternatively, the operating temperature of thechlorination zone may be about 60° C. or more, about 75° C. or more,about 90° C. or more, or about 120° C. or more. In embodiments of theinvention, the operating temperature of the chlorination zone may befrom about 10° C. to about 40° C., from about 40° C. to about 80° C., or80° C. or above.

In embodiments of the present invention, where chlorination of the C₃chlorinated alkane starting material results in the formation of firstand second C₃ chlorinated alkane isomers, those isomers are present in amolar ratio of about 95:5, about 90:10, about 80:20, about 70:30, about60:40, about 50:50, about 40:60, about 30:70, about 20:80, about 10:90,or about 5:95 to about 5:95, about 10:90, about 20:80, about 30:70,about 40:60, about 50:50, about 60:40, about 70:30, about 80:20, about90:10 or about 95:5.

Chlorination may be carried out at any temperature which enables theconversion of the starting material to the chlorinated alkane isomers ofinterest. Optimal temperatures will depend on the specific chlorinatedalkane starting material which is employed and/or the degree ofchlorination that is required (e.g. the number of chlorine atoms to beadded to the starting material).

In embodiments of the invention, it has been found that relatively mildreaction conditions enable the progress of the reaction to becontrolled, while enabling the chlorination reaction to proceed at anacceptable rate and minimizing the production of unwanted impurities,such as over-chlorinated impurities. For example, operating temperatureswithin the range of about −30° C., about −20° C., about −10° C., about0° C. or about 20° C. to about 40° C., about 60° C., about 80° C., about100° C., about 120° C., about 150° C., about 170° C. or about 200° C.may be employed in the chlorination zone.

Depending on the type of reactor, the intended molar ratio of theplurality of isomers, the starting material and/or the type of catalyststo be used the chlorination step in the processes of the presentinvention may be carried out at a low temperature range (e.g. about −30°C., about −20° C., about −10° C. to about 10° C., about 20° C. or about30° C.) at a moderate temperature range (e.g. about −30° C., about −20°C., about −10° C., about 0° C., about 10° C., about 20° C. or about 30°C. to about 50° C., about 70° C. or about 100° C.), or at a highertemperature range (e.g. about 50° C., about 70° C., about 90° C. orabout 110° C. to about 150° C., about 170° C. or about 200° C.).

As purely illustrative examples, the inventors have found thatchlorination reactions catalyzed by UV and/or visible light only can beoperated at a low temperature range as outlined above, whilechlorination reactions catalysed only by Lewis acid catalysts can beoperated at a higher temperature range as outlined above. Inarrangements where chlorination reactions of the present invention arecatalyzed by UV and/or visible light and Lewis acids, a moderatetemperature range may be employed.

The inventors have found that by operating the chlorination reaction atsuch temperatures in, e.g. a continuous mode, an advantageous balance isreached between good reaction efficiency and reduction in the formationof unwanted impurities.

The chlorination zone may be operated at subatmospheric pressure,atmospheric pressure or superatmospheric pressure.

Any type of reactor which can provide a chlorination zone in which thechlorination of C₃ chlorinated alkane starting material to produce areaction mixture comprising C₃ chlorinated alkane isomers can beachieved may be employed in the processes of the present invention.Specific examples of reactors that may be used in the processes of thepresent invention to provide the chlorination zone are column reactors(e.g. column gas-liquid reactors), tubular reactors, bubble columnreactors, plug/flow reactors (e.g. tubular plug/flow reactors) andstirred tank reactors (e.g. continuous stirred tank reactors) andphotoreactors (such as falling film photoreactors).

The process of the present invention may be carried out in a singlechlorination zone or in a plurality of chlorination zones. Where aplurality of chlorination zones are employed (for example, 2, 3, 4, 5, 6or more chlorination zones), these may be operated in sequence (i.e.such that reaction mixture is passed along a number of chlorinationzones) and/or in parallel. In embodiments of the invention, chlorinationof the starting material is achieved in a series of continuously stirredtank reactors operated in sequence.

In embodiments in which photochlorination of the C₃ chlorinated alkanestarting material is carried out, the reactor is preferably providedwith a source of UV and/or visible light and/or a port through whichlight can pass into the chlorination zone. Where a solid (e.g.particulate) catalyst (e.g. a Lewis acid catalyst) or liquid catalyst isemployed, this may be fed directly into the chlorination zone.Additionally or alternatively, this may be dissolved or dispersed in theC₃ chlorinated alkane starting material upstream of the chlorinationzone.

Those skilled in the art will recognise that where different types ofreactors are used, operating conditions and/or the degree of conversionof the C₃ chlorinated alkane starting material to the chlorinated alkaneisomeric product may be modified to optimise the chlorination process.As a purely illustrative example, in a continuous chlorination processin which UV and/or visible light is used to catalyse the reaction (e.g.in which the chlorination zone is provided in a continuously stirredtank photoreactor) with standard vacuum distillation being employed, themolar ratio of C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers may be limited to 60:40 and/or the operating temperatureof the chlorination zone may be within the range of about 30° C. toabout 30° C. In alternative arrangements, in which a circulation or loopreactor is used to provide the chlorination zone and the reactionmixture is subjected to direct distillation, the molar ratio of C₃chlorinated alkane starting material:C₃ chlorinated alkane isomers maybe limited to 90:10 and/or the operating temperature of the chlorinationzone may be as high as about 120° C. In a still further embodiment, inwhich a photoreactor, for example a falling film tubular photoreactor isused, the molar ratio of C₃ chlorinated alkane starting material:C₃chlorinated alkane isomers may be limited to 40:60.

Reactors used in the present invention may be divided into differentzones each having different flow patterns and/or different operatingtemperatures/pressures. For example, the chlorination step may beperformed in a reactor including a plurality of reaction zones. Thosezones may be operated at different temperatures and/or pressures.

Additionally or alternatively, reactors used in the processes of thepresent invention may be provided with external circulation loops. Theexternal circulation loops may optionally be provided with coolingand/or heating means- and/or with devices for selectiveextraction/removal of the chlorinated alkane isomers from thechlorination zone.

As those skilled in the art will recognise, the chlorination zone can bemaintained at target temperatures through use of cooling/heatingelements such as cooling tubes, cooling jackets, cooling spirals, heatexchangers, heating fans, heating jackets or the like. In embodiments inwhich photochlorination is carried out and UV and/or visible light issupplied to the chlorination zone using glass tube, the tube mayadditionally be configured to enable the flow therethrough of a coolant(e.g. water).

The operating temperature in the chlorination zone may be controlled byany temperature control means known to those skilled in the art, forexample heating and/or cooling means such as heating/cooling jackets,heating/cooling loops either internal or external to the reactor,cooling spirals, heat exchangers, heating fan and the like. Additionallyor alternatively, the temperature may be controlled by controlling thetemperature of material/s added into the chlorination zone, thus,controlling the temperature of the reaction mixture therein. Thereaction mixture is maintained in the chlorination zone for a time andunder conditions sufficient to achieve the required level of conversionof the chlorinated alkane starting material to the chlorinated alkaneisomers.

Those skilled in art will recognise that, in certain embodiments, thereaction zones utilised at any stage in the processes of the presentinvention (e.g. chlorination and/or dehydrochlorination) may employagitation means, e.g. stirrers, followers, flow channeling means or thelike.

As mentioned above, the proportion of the chlorinated alkane startingmaterial present in the reaction mixture present in the chlorinationzone can be controlled by extracting the isomers of interest from thechlorination zone. This extraction may be carried out on a batch-wise orcontinuous basis. For the avoidance of doubt, where reference is made inthe present application to the continuous extraction of material fromthe zones employed in the processes of the present invention, thisshould not be assigned a purely literal meaning. One skilled in the artwould recognise that, in such embodiments, reaction mixture may beremoved on a substantially continuous basis while the chlorination zoneis at operating conditions and, if its purpose is to set up a steadystate reaction, once the reaction mixture therein has attained therequired steady state.

Separation of the isomers of interest from the reaction mixture presentin the chlorination zone can be achieved using any technique known toone skilled in the art. For example, one or more distillation steps maybe employed.

The reaction mixture produced in the chlorination zone will compriseunreacted C₃ chlorinated alkane starting material, a plurality of C₃chlorinated alkane isomers, and potentially impurities such as thoseoutlined above, e.g. isomeric impurities, under-chlorinated impurities,over-chlorinated impurities, compounds having a different number ofcarbon atoms than the isomers and/or chlorinated alkene isomers.

In embodiments where post-chlorination distillation is conducted, one ormore distillation steps may be performed. Such steps may be performeddirectly on reaction mixture present in the chlorination zone and/or onreaction mixture extracted from the chlorination zone before and/orafter any post-chlorination treatment steps such as an aqueous treatmentstep.

Post-chlorination distillation results in a plurality of C₃ chlorinatedalkane isomer stream being obtained which is rich in or consists of thetarget plurality of isomers (e.g. 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane).

Additionally, one or more of the following streams may be obtained:

-   -   unreacted C₃ chlorinated alkane starting material (e.g.        1,1,1,3-tetrachloropropane) stream which is rich in or consists        of the C₃ chlorinated alkane starting material,    -   one or more single isomer streams rich in or consisting of one        of the target isomers (e.g. 1,1,1,2,3-pentachloropropane or        1,1,1,3,3-pentachloropropane) where, owing to the boiling points        of the isomers and/or distillation conditions it is possible to        selectively distil at least a proportion of one of the isomers.    -   one or more distillation residue streams rich in or consisting        of under chlorinated impurities, over chlorinated impurities        and/or impurities having a different number of carbon atoms to        the isomers.

Those skilled in the art will recognize that streams said to be rich inparticular compounds (or pluralities of such compounds) will comprisethe specified compounds as the principal components, i.e. they willcontain at least 50% of the specified compound/s. In preferredembodiments, one, some or all of the above-mentioned streams comprise atleast about 80%, at least about 90%, at least about 95%, at least about97%, at least about 99%, at least about 99.5%, or at least about 99.9%of the specified compound/s.

For the avoidance of doubt, as used herein the term ‘stream’ should beinterpreted broadly, thus encompassing portion/s of compound extractedfrom a reaction mixture with at least some degree of selectivity using adistillation technique or the like, regardless of whether, owing to thedistillation technique in question, those portion/s are actuallycollected as fractions or streams.

In preferred embodiments, the plurality of C₃ chlorinated alkane isomerstream and/or the one or more single isomer stream/s, where obtained,comprise:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about 10 ppm or        less than about 5 ppm of under chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        over chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        chlorinated alkene compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm or less than about 5        ppm of compounds having a different number of carbon atoms than        the isomers,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm less than about 5        ppm, or less than about 2 ppm of oxygenated organic impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 10 ppm or less than about ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 10 ppm or less than about 5 ppm water.

For the avoidance of doubt, one some or all of the streams outlinedabove may be obtained in the same or different distillations. Forexample, all four of the streams may be obtained in a singledistillation step employing distillation apparatus that enablesmultiples streams of distillate to be obtained simultaneously orsequentially.

Alternatively, each of the streams outlined above may be collectedindividually in separate distillation steps.

As a further alternative, one of the streams mentioned above may beobtained in a first distillation step, for example one which may beconducted directly on reaction mixture present in the chlorination zone.The reaction mixture may then be fed to distillation apparatus remotefrom the chlorination zone and subjected to a single or multipledistillation steps to one or more of the other streams mentioned above.

In one embodiment, whether a single or multiple post-chlorination stepsare conducted, a single isomer stream may be collected. One skilled inthe art will recognize that in embodiments where a single isomer streamis distilled from the mixture, this will affect the ratio of isomerspresent in the plurality of isomers in the mixture.

This, alongside the optional selection of chlorination catalysts asdiscussed above, enables the ratio of the isomers present in theplurality to be carefully controlled such that the optimal isomericratio for the downstream processing application can be achieved.

Thus, in embodiments of the invention, a single isomer may be separatedfrom a mixture containing a plurality of isomers having a first isomericratio, resulting in the isomeric ratio of that plurality of isomers inthe mixture being altered in favour of the other isomer/s remaining inthe mixture. For example, in such embodiments, the proportion of theother isomer/s remaining in the mixture may be increased by at leastabout 2%, about 5%, about 7%, about 10%, about 15%, about 25%, or about50%.

Put another way, in embodiments of the invention in which the pluralityof C₃ chlorinated alkane isomers consists of a pair of isomers, a firstand a second isomer, distillation of the mixture to obtain a singleisomer stream rich in or consisting of the second isomer will increasethe proportion of the first isomer in the plurality of C₃ chlorinatedalkane isomers. Alternatively, where distillation of the mixture toobtain a single isomer stream rich in or consisting of the first isomeris carried out, this will increase the proportion of the second isomerin the plurality of C₃ chlorinated alkane isomers. In such embodiments,the proportion of the first or second isomer in the plurality of isomersis increased by about 3% or more, by about 5% or more, by about 10% ormore, or by about 20% or more.

In such embodiments, the single isomer stream may be obtained before anyother streams are obtained from the mixture. This may be achieved usingseparate distillation apparatus from that used to obtain the pluralityof C₃ chlorinated alkane isomer stream and any other streams.Alternatively, the same apparatus may be used, with the single isomerstream being obtained prior to or simultaneously with the plurality ofC₃ chlorinated alkane isomer stream and any other streams beingobtained.

Where obtained, the unreacted C₃ chlorinated alkane starting materialstream may be fed back in to the chlorination zone. Additionally oralternatively, the plurality of C₃ chlorinated alkane isomer streamand/or the single isomer stream/s (if obtained) may be subjected todownstream processing steps, e.g. the selective dehydrochlorinationprocess discussed below.

In embodiments of the invention, the C₃ chlorinated alkane startingmaterial stream is obtained by direct distillation using distillationapparatus in communication with the chlorination zone. In suchembodiments, the reaction mixture may then be extracted from thechlorination zone/direct distillation apparatus and subjected todownstream distillation steps and/or other processing steps. Thoseskilled in the art will recognize that in such embodiments, distillationof the C₃ chlorinated alkane starting material stream will result in theproportion of the plurality of C₃ chlorinated alkane isomers present inthe mixture being increased, potentially beyond the molar ratio limit of60%.

The distillation residue stream/s may be discarded and/or subjected tofurther treatment steps such as incineration or high temperaturechlorinolysis (to produce useful materials (e.g. carbon tetrachloridewhich can be used to produce the starting chlorinated alkane1,1,1,3-tetrachloropropane, for example via the processes disclosed inW2016/058566 and/or tetrachloroethene) at high purity).

Separation of the impurities included in this stream from the targetisomers is preferable owing to the negative influence of the reactiveimpurities including over chlorinated impurities (e.g.1,1,1,3,3,3-hexachloropropane) in downstream conversion steps, forexample in dehydrochlorination steps as these can produce furtherundesired impurities which will contaminate the final products ofinterest.

As mentioned herein, one of the advantages provided by the presentinvention is that the plurality of C₃ chlorinated alkane isomers areproduced at high levels of purity meaning that less purification stepsare required to obtain high quality feedstocks that can be used indownstream processes (such as hydrofluorination reactions) as comparedto processes of the prior art. Accordingly, in embodiments of theinvention, the number of distillation steps that are performed on the C₃chlorinated alkane isomers following the chlorination of the C₃chlorinated alkane starting material and prior to those isomers beingused in a downstream chemical conversion reaction (e.g.dehydrochlorination) is limited to 3, 2 or 1.

As mentioned above, distillation of the reaction mixture may be directdistillation, i.e. where the distillation apparatus is in directcommunication with the chlorination zone enabling the reaction mixtureto be passed directly into the distillation apparatus.

Additionally or alternatively, reaction mixture may be extracted fromthe chlorination zone before being fed into distillation apparatusremote from the chlorination zone.

Any distillation apparatus or techniques which can be used toselectively extract a stream rich in the C₃ chlorinated alkane isomersof interest from the reaction mixture present in the chlorination zonemay be employed.

As an example of an arrangement which may be used to distill reactionmixture to produce a C₃ chlorinated alkane isomer rich stream, a“circulation” or “loop” chlorination reactor can be employed, in whichreaction mixture is continuously removed from the reaction zone andtreated using a distillation device, preferably operated under vacuum,located in the external circulation. In the distillation device, the C₃chlorinated alkane starting material is distilled off and fed back tothe chlorination zone while the isomer mixture is the distillationresidue which is taken forward for further processing, for example oneor more distillation steps conducted in distillation apparatus remotefrom the reactor in which C₃ chlorinated alkane isomer stream/s, singleisomer stream/s and or distillation residue stream/s are obtained. Theuse of such apparatus advantageously suppresses serial reactions whichotherwise would lead to the formation of over chlorinated side productsand can utilize some or all of the heat of reaction which canadvantageously reduce operating cost.

In embodiments of the invention, distillation to obtain one some or allof the streams mentioned above can be achieved in a single distillationapparatus, for example a batch distillation system comprising, e.g. abatch column, a boiler, a condenser and distillate tanks. Alternatively,one some or all of those streams could be obtained using a series ofcontinuous distillation systems comprising, e.g. columns, boilers,condensers, and distillate tanks.

It has been found that, under certain operating conditions, the use ofhigh distillation temperatures can lead to the formation of unwantedimpurities. Thus, where distillation step/s are employed in theprocesses of the present invention, distillation may be conducted at atemperature of (i.e. the liquid being subjected to distillation is notexposed to temperatures greater than) about 130° C. or less, about 120°C. or less, about 110° C. or less, about 105° C. or less, about 100° C.or less, about 90° C. or less or about 80° C. or less.

To facilitate distillation at modest temperatures, distillation may becarried out at reduced pressure. For example, distillation may beconducted under vacuum. Where vacuum distillation is carried out, thevacuum conditions may be selected such that the distillation may beconducted at a low temperature.

As mentioned above, any distillation equipment known to those skilled inthe art can be employed in the processes of the present invention, forexample a distillation boiler/column arrangement. However, it hasunexpectedly been found that the formation of chlorinated alkanedegradation products can be minimised if distillation apparatus formedof certain materials are avoided.

In embodiments of the invention in which mixtures comprising chlorinatedalkane compounds are subjected to one or more distillation steps, thedistillation apparatus employed in one, some or all of those steps maybe configured such that all or some of its components which, in use ofthe distillation apparatus, would come into contact with the distillateor process fluid, are produced from fluoropolymers,fluorochloropolymers, glass, enamel, phenolic resin impregnatedgraphite, silicium carbide and/or fluoropolymer impregnated graphite.

Advantageously, the use of a chlorinated alkane starting material withvery low metal content and distillation apparatus which is free ofmetallic components that contact the working fluid during use lead toimproved conversion to the target products and with reduced loss to sideproducts.

In embodiments of the process of the invention, the distillationtechnique/apparatus employed may enable multiple streams to be extractedfrom the reaction mixture. For example, multiple streams of the isomersof interest may be extracted from the reaction mixture, where thoseisomers have a wide range of boiling points. These streams or fractionscan then be blended to form the reaction mixture comprising a pluralityof C₃ chlorinated alkane isomers, optionally at a desired ratio of theisomers.

The inventors have determined that, under certain operating conditions,the presence of dissolved or entrained chlorine in the reaction mixturecomprising C₃ chlorinated alkane isomers may result in the formation ofunwanted impurities in downstream reactions in which those isomers (orcompounds formed therefrom) are employed. Thus, in embodiments of theinvention, reaction mixture comprising a plurality of C₃ chlorinatedalkane isomers extracted from the chlorination zone or obtained as a C₃chlorinated alkane isomer rich stream upon distillation may compriseless than about 0.1%, less than about 0.05% or less than about 0.01%chlorine. The control of the chlorine content in these mixtures can beachieved using any technique known to those skilled in the art. Forexample, the chlorine content can be controlled through the carefulcontrol of the amount of chlorine supplied to the chlorination zone orby control of the ratio of chlorinated alkane startingmaterial:chlorinated alkane product isomers in the chlorination zone. Asdiscussed herein, the careful control of the amount of chlorine suppliedto the chlorination zone advantageously also enables the rate ofconversion of the C₃ chlorinated alkane starting material to becontrolled.

The inventors have also found that, under certain operating conditions,the exposure of the reactants used in the processes of the presentinvention as well as the compounds formed in those processes to sourcesof oxygen and/or moisture, including air, water vapour and/or water canlead to the formation of unwanted impurities. Thus, in embodiments ofthe present invention, chlorination and/or distillation may be conductedin the absence of oxygen.

Even where steps are taken to minimise the exposure of thereactants/products of the processes of the present invention fromexposure to oxygen and/or moisture, under certain operating conditions,the formation of oxygenated organic compounds (which have been found bythe inventors to be problematic in certain downstream processes in whichthe products of the processes of the present invention may be employed)cannot be totally prevented. Accordingly, where such compounds arepresent in the reaction mixture and/or a C₃ chlorinated alkane isomerrich stream, that mixture/stream may be processed to remove the unwantedoxygenated organic compounds therefrom.

Indeed, it will be appreciated that, regardless of how mixtures of C₃chlorinated alkane isomers are produced, such a step can be employed toreduce the content of (or ideally remove) oxygenated organic compoundsfrom those mixtures. Thus, according to a further aspect of theinvention, there is provided a process for purifying a mixturecomprising at least two C₃ chlorinated alkane isomers and one or moreoxygenated organic compounds comprising feeding the mixture into anaqueous treatment zone, contacting the mixture with an aqueous mediumand extracting a treated mixture comprising reduced levels of oxygenatedcompounds.

The aqueous treatment step, where conducted, may be carried out beforenone, one, some or all of any distillation steps that are carried out.

Advantageously, the aqueous treatment step can achieve removal ofoxygenated impurities in two ways. Firstly, the aqueous medium canachieve physical process extraction of oxygenated compounds.Additionally, for some compounds, these may be converted by hydrolysisto more easily separable compounds. Propanoyl chlorides are an exampleof compounds which are firstly hydrolysed to form their correspondingcarboxylic acids which can then be extracted to an aqueous phase.

In such embodiments, the mixture subjected to the aqueous treatment stepmay be reaction mixture extracted from the chlorination zone.Alternatively, the mixture may be a plurality of C₃ chlorinated alkaneisomer stream obtained via distillation from the reaction mixture. In afurther alternative arrangement, the mixture subjected to aqueoustreatment may be partially distilled reaction mixture, i.e. reactionmixture extracted from the chlorination zone from which one or more ofan unreacted C₃ chlorinated alkane starting material stream, one or moresingle isomer streams and/or one or more distillation residue streamshas already been obtained via distillation.

In processes of the present invention in which such an aqueous treatmentstep is performed, the step may be repeated any number of times toobtain a treated mixture of acceptable purity. For example, the steps ofcontacting the mixture with an aqueous medium and extracting a treatedmixture therefrom may be repeated 1, 2, 3, 4, 5, 6, 7, 8, 9 or moretimes. Temperatures for this treatment may range from about 0 to about100° C. for the alkane. The corresponding batch time or mean residencetime for this step may be around 0.01 to about 10 hours.

In embodiments of the invention in which an aqueous treatment step isconducted, the treated mixture may comprise oxygenated organic compoundsin amounts of about 1000 ppm or less, about 500 ppm or less, about 200ppm or less, about 100 ppm or less, about 50 ppm or less, about 20 ppmor less, about 10 ppm or less, about 5 ppm or less or about 2 ppm orless.

The treated mixture also preferably comprises a plurality of C₃chlorinated alkane isomers at a purity of about 95% or higher, about 97%or higher, about 99% or higher, about 99.5% or higher, about 99.7% orhigher, about 99.8% or higher or about 99.9% or higher, and furthercomprises:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about 10 ppm or less than        about 5 ppm of under chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        over chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        chlorinated alkene compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm or less than about 5        ppm of compounds having a different number of carbon atoms than        the isomers,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm less than about 5        ppm, or less than about 2 ppm of oxygenated organic impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 10 ppm or less than about 5 ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 100 ppm or less than about 5 ppm water.

Examples of aqueous media which may be employed in the aqueous treatmentstep include water and steam. Additionally or alternatively, acid(mineral, organic, etc.) may also be added to provide a pH to themixture in the aqueous treatment zone of about 6 or lower, about 4 orlower, or about 2 or lower.

Performance of an aqueous treatment step is preferable as this reducesthe content of oxygenated organic compounds present as impurities in thecomposition comprising a plurality of C₃ chlorinated alkane isomers.Examples of oxygenated organic compounds include chlorinated alkanols,chlorinated acid chlorides, chlorinated acids, chlorinated ketones orchlorinated aldehydes.

In processes of the present invention in which an aqueous treatment stepis performed, the mixture fed into the aqueous treatment zone may have alow chlorine content, for example about 0.8% or less, about 0.5% orless, about 0.1% or less, about 0.05% or less or about 0.01% or less.For the avoidance of doubt, where reference is made in this context tochlorine, this encompasses free chlorine, unreacted chlorine, anddissolved chlorine. Chlorine which is bonded to atoms other thanchlorine should not be considered.

In embodiments of the invention, the aqueous treatment zone is in awashing tank, for example a washing stirred tank. In such embodiments,the mixture may be washed with water and/or steam

Once the mixture has been contacted with the aqueous medium, it may besubjected to one or more treatment steps. For example, the mixture canbe extracted from the aqueous treatment zone and distilled (preferablyunder reduced pressure and/or low temperature) to provide the treatedmixture.

Additionally or alternatively, in embodiments of the invention, abiphasic mixture may be formed in the aqueous treatment zone. Separationof the phases can then occur, for example extractive separationinvolving the hydrolysis and extraction of undesired polar ormedium-polar oxygenated compounds into the water.

In such embodiments, the phase separation step involves the organicphase containing the chlorinated alkane isomers being separated from theaqueous waste phase. This may be achieved by the sequential extractionof the phases from the aqueous treatment zone. Alternatively, thebiphasic mixture could be extracted from the aqueous treatment zone andsubjected to a phase separation step remote from the aqueous treatmentzone.

The aqueous treatment steps can be repeated if required, for example,one, two, three or more times or periodically in an extraction column,optionally with a suitable chemical reaction.

The organic phase obtained from the aqueous treatment step mayoptionally be dried, e.g. using a desiccant such as calcium chloride.

As mentioned above, the main aim of the aqueous treatment step, ifperformed is to reduce the content of oxygenated impurities which arepresent in the mixture subjected to that step.

In embodiments in which a Lewis acid is employed as a catalyst in thechlorination reaction, a catalyst removal step may be performed. Thismay be performed as a washing step, employing some or all of theconditions, techniques and apparatus discussed below in connection withthe post-dehydrochlorination washing step.

Advantageously, in embodiments in which a washing step is performed,that washing step is conducted such that it both results in extractionof the catalyst from the mixture subjected to the washing step but alsoserves to reduce the content of oxygenated impurities from the mixtureand thus additionally has the function of an aqueous treatment step.

In embodiments of the present invention, the mixture comprising the C₃chlorinated alkane isomers obtained from the chlorination step (or, ifperformed, the aqueous treatment step/s) is subjected to a purificationstep, for example a distillation step. The distillation step may beconducted using the same (or different) apparatus and conditions asemployed in the post-chlorination distillation step discussed above.Thus, in embodiments of the invention, a step of distilling the treatedmixture to obtain a stream comprising the plurality of C₃ chlorinatedalkane isomers at higher purity than in the mixture fed in to theaqueous treatment zone may be conducted. The distillation may beconducted at a temperature of about 130° C. or less.

The processes outlined herein provide a plurality of C₃ chlorinatedalkane isomers.

Those skilled in the art will recognise that chlorination of C₃chlorinated alkane starting materials will, depending on the reactionconditions employed, typically and to a certain extent consistentlyproduce the same plurality of isomers, i.e. the same compounds atbroadly speaking the same ratios.

The present invention is based upon the inventors identifying theapplicability of pluralities of C₃ chlorinated alkane isomers indownstream reactions. Such isomers have previously been seen asundesirable on the basis that the isomers of interest are provided as acomponent in a mixture and, in many cases, are difficult to separatefrom other isomers, for example on the basis of similar boiling points.Indeed, substantial effort has been made to provide such alkanes havingthe highest possible degree of purity.

As mentioned above, the inventors have determined that the isomermixtures of the present invention may be employed in a range ofindustrially applicable and commercially viable processes.

Thus, according to a further aspect of the present invention, there isprovided a process for producing a C₃ chlorinated alkene comprisingproviding a mixture comprising a plurality of C₃ chlorinated alkaneisomers, the boiling point of at least two of the plurality of C₃chlorinated alkane isomers differing by ≦about 15° C., comprisingsubjecting the mixture to a selective dehydrochlorination step in adehydrochlorination zone in which one of the at least two C₃ chlorinatedalkane isomers, a first C₃ chlorinated alkane isomer, is selectivelyconverted to a respective first C₃ chlorinated alkene without thesubstantial dehydrochlorination of any of the other of the plurality ofC₃ chlorinated alkane isomers.

Advantageously, the process of this aspect of the present inventionresults in the formation of a first chlorinated alkene isomer having aboiling point which is sufficiently different (typically lower) than theboiling point of the chlorinated alkane isomers. Thus, the chlorinatedalkene product of interest can be efficiently and easily isolated, forexample, by distillation.

The process of this aspect is advantageous as it enables C₃ chlorinatedalkane isomers which may otherwise be difficult to separate to bedehydrochlorinated with a high degree of selectivity such that one ofthe chlorinated alkane isomers is converted to a corresponding alkenewithout the substantial conversion of any of the other alkane isomerspresent. By ‘without substantial conversion’, it is meant that less thanabout 5%, less than about 2%, less than about 1%, less than about 0.5%,less than about 0.2%, less than about 0.1%, less than about 0.05%, lessthan about 0.02% or less than about 0.01% of any of the other C₃chlorinated alkane isomers present in the mixture are dehydrochlorinatedto their respective alkene, by weight of the respective alkane isomer.

For the avoidance of doubt, where reference is made to first and secondC₃ chlorinated alkane isomers present in the dehydrochlorination zoneand mixtures downstream of the dehydrochlorination step, these terms arenot necessarily applicable to C₃ chlorinated alkane isomers formed inthe chlorination step discussed herein, and vice versa. For example, anisomeric pair of 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane could be produced in the chlorination step,with 1,1,1,2,3-pentachloropropane being referred to, within the contextof that reaction and downstream processing steps (prior todehydrochlorination), as the first isomer and1,1,1,3,3-pentachloropropane being referred to as the second isomer.However, if that plurality of isomers is then employed in thedehydrochlorination step, then 1,1,1,3,3-pentachloropropane may bereferred to as the first C₃ chlorinated alkane isomer, within thecontext of that reaction and its downstream processing steps, and1,1,1,2,3-pentachloropropane may be referred to as the second C₃chlorinated alkane isomer. Alternatively, 1,1,1,2,3-pentachloropropanemay be referred to as the second C₃ chlorinated alkane isomer, withinthe context of the dehydrochlorination reaction and its downstreamprocessing steps, and 1,1,1,3,3-pentachloropropane may be referred to asthe first C₃ chlorinated alkane isomer.

The selective dehydrochlorination of one of the C₃ chlorinated alkaneisomers is preferably at least about 95%, about 98%, about 99%, about99.5% or about 99.7% selective in favour of the conversion of one isomerpresent in the mixture.

While U.S. Pat. No. 8,987,535 provides a process for preparing apotentially useful isomer mix, a successful treatment of this mixture toyield high grade individual compounds has not been achieved. The presentinventors have developed a process for preparing a high grade mix ofisomers which minimizes or ideally prevents the formation of sideimpurities. According to the processes of the present invention, one ofthose isomers can selectively be converted to its respective C₃chlorinated alkene which can then be easily isolated on an industrialplant scale, in preferably continuous mode, and using common upstreamfeedstocks.

For ease of reference, the first C₃ chlorinated alkane isomer to beselectively dehydrochlorinated to yield a respective chlorinated alkeneis referred to as the first C₃ chlorinated alkane isomer. Likewise, thealkene obtained from the dehydrochlorination step is referred to as thefirst C₃ chlorinated alkene.

As mentioned above, the mixture comprising a plurality of C₃ chlorinatedalkane isomers may comprise any number of component isomers (i.e.isomers being present in an amount of 1% or more by weight of the totalisomer mixture). However, in this aspect of the invention, at least twoof the component isomers must have a boiling point which varies by≦about 20° C. In embodiments of the invention, the boiling point of theat least two component isomers may vary by a lesser degree, e.g. by≦about 15° C., by ≦about 10° C. or by ≦about 5° C.

While the selective conversion of one of the chlorinated alkane isomersto its respective chlorinated alkene facilitates the straightforwardseparation of that alkene from its chlorinated alkane, it has been foundthat mixtures of chlorinated alkanes and chlorinated alkenes obtainablefrom this aspect of the present invention are of commercial value.Examples of such specific combinations include i)1,1,1,2,3-pentachloropropane and 1,1,2,3-tetrachloro-1-propene(HCO-1230xa), ii) 1,1,3,3-tetrachloro-1-propene (HCO-1230za) and1,1,1,2,3-pentachloropropane (HCC-240db), iii)1,1,3,3-tetrachloro-1-propene (HCO-1230za), 1,1,1,2,3-pentachloropropane(HCC-240db) and 1,1,2,3-tetrachloro-1-propene (HCO-1230xa), iv)1,1,1,3,3-pentachloropropane (HCC-240fa), 1,1,3,3-tetrachloro-1-propene(HCO-1230za), and/or 1,3,3,3-tetrachloro-1-propene (HCO-1230zd).

The dehydrochlorination step of this aspect of the invention may beconducted in any phase, including the liquid or gas phase.

For the avoidance of doubt, the mixture comprising a plurality of C₃chlorinated alkane isomers may be obtainable from the processesdiscussed herein. Additionally or alternatively, the plurality ofisomers may be obtained from an alternative process for preparing suchcompositions.

Regardless of how the mixture comprising a plurality of C₃ chlorinatedalkane isomers is prepared, it preferably has low levels of impurities.

For example, that mixture comprising the plurality of C₃ chlorinatedalkane isomers preferably has a purity (i.e. a content as percentage byweight) of about 95% or higher, about 97% or higher, about 99% orhigher, about 99.5% or higher, about 99.7% or higher about 99.8% orhigher, or about 99.9% or higher and preferably further comprises:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about ppm or        less than about 5 ppm of under chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        over chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        chlorinated alkene compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm or less than about 5        ppm of compounds having a different number of carbon atoms than        the isomers,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about 100 ppm less than about        5 ppm, or less than about 2 ppm of oxygenated organic        impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 100 ppm or less than about 5 ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 100 ppm or less than about 5 ppm water.

In embodiments of this process of the invention, the mixture which issubjected to selective dehydrochlorination may comprise a first and asecond isomer present in a molar ratio of about 95:5, about 90:10, about80:20, about 70:30, about 60:40, about 50:50, about 40:60, about 30:70,about 20:80, about 10:90 or about 5:95 to about 5:95, about 10:90, about20:80, about 30:70, about 40:60, about 50:50, about 60:40, about 70:30,about 80:20, about 90:10 or about 95:5.

In embodiments of the invention, one, two, or all of the chlorinatedalkane isomers formed in the chlorination zone are compounds having atrichlorinated terminal carbon atom.

The plurality of isomers in the mixture may be i)1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane, ii)1,1,1,2,3-pentachloropropane and 1,1,2,2,3-pentachloropropane, or iii)1,1,2,2,3-pentachloropropane and 1,1,1,2,2-pentachloropropane. In theisomeric pairs outlined in this paragraph, the first listed isomer maybe the first C₃ chlorinated alkane isomer or the second C₃ chlorinatedalkane isomer, and the second listed isomer may be the other of thefirst C₃ chlorinated alkane isomer or the second C₃ chlorinated alkaneisomer.

Thus, according to a further aspect of the present invention, the use ofa mixture comprising a plurality of C₃ chlorinated alkane isomers in adehydrochlorination step is provided, wherein the mixture has a purity(i.e. a content as percentage by weight) of about 95% or higher, about97% or higher, about 99% or higher, about 99.5% or higher, about 99.7%or higher about 99.8% or higher, or about 99.9% or higher of theplurality of C₃ chlorinated alkane isomers and preferably furthercomprises:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about ppm or        less than about 5 ppm of under chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        over chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        chlorinated alkene compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm or less than about 5        ppm of compounds having a different number of carbon atoms than        the isomers,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm less than about 5        ppm, or less than about 2 ppm of oxygenated organic impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 10 ppm or less than about 5 ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 10 ppm or less than about 5 ppm water.

The mixture comprising the plurality of C₃ chlorinated alkane isomersemployed in this aspect of the present invention may additionallycomprise any property of mixtures used as starting materials fordehydrochlorination reactions described herein in connection with otheraspects of the invention.

Those skilled in the art will be familiar with techniques and apparatusthat may be employed in dehydrochlorination reactions. Such processesmay be employed in the process of this aspect of the present inventionprovided that they enable the selective dehydrochlorination of a firstC₃ chlorinated alkane isomer without the substantial conversion of anyof the other isomers present in the mixture. While dehydrochlorinationtechniques and apparatus were known, the use of such processes toselectively dehydrochlorinate one isomer from a plurality of isomers hasnot previously been conducted and is not intuitive. Operating a processin this way enables the successful and efficient recovery of high gradeindividual products.

It has been found that alkaline dehydrochlorination as employed in theprior art may not be industrially feasible in the processes of thepresent invention as a result of economic and environmental drawbacks.Further, a substantial amount of carbonyl compounds (found to beparticularly problematic in downstream processes by the inventors) areformed during alkaline hydroxide dehydrochlorination. Additionally, thepresence of alkaline agents in dehydrochlorination to form certainalkenes (e.g. 1,1,3,3-tetrachloropropene) can result in the formation ofexplosive mixtures. In tests performed by the inventors, it was foundthat alkaline dehydrochlorination of the mixture of1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane (80:20ratio), does not give the required selectivity towards one chlorinatedalkene; both 1,1,3,3-tetrachloropropene and 2,3,3,3-tetrachloropropeneare produced.

Particularly preferred dehydrochlorination processes are disclosed inWO2016/0580567, the contents of which are incorporated by reference.

The reaction mixture is maintained in the dehydrochlorination zone for aperiod sufficient to enable the reaction (the conversion of first C₃chlorinated alkane to the first C₃ chlorinated alkene) to proceed to therequired degree of completion. In embodiments of the invention, in whichdehydrochlorination occurs in the liquid phase, the residence time ofthe reaction mixture in the dehydrochlorination zone may range fromabout 0.1, about 0.2, about 0.5, about 1, about 1.5, about 2, about 2.5or about 3 to about 5 hours, about 7 hours, about 9 hours or about 10hours.

In embodiments in which dehydrochlorination is conducted in the liquidphase, the operating temperature of the dehydrochlorination zone may bein the range of about 50° C., about 70° C., about 100° C. or about 120°C. to about 150° C., about 170° C., about 200° C. or about 250° C.

The dehydrochlorination zone may be operated at subatmospheric pressure,atmospheric pressure or superatmospheric pressure. In embodiments of theinvention, the dehydrochlorination zone is operated at atmosphericpressure, or at a pressure of about kPa to about 400 kPa, about 40 kPato about 200 kPa, or about 70 kPa to about 150 kPa.

Any catalyst which increases the rate of the dehydrochlorinationreaction may be employed in the processes of the present invention. Inembodiments, the catalyst comprises a metal. In such embodiments, themetal may be present in solid form (e.g. where the catalyst is iron, itmay be present as particulate iron (e.g. iron filings or iron powder)iron mesh, iron wire, packing (structured or random), fixed bed, fluidbed, dispersions in liquid, etc. or in alloys containing iron formed inany such way, e.g. carbon steel), and/or as a salt (e.g. where thecatalyst is iron, it may be present as ferric chloride, ferrouschloride, etc.). Additionally or alternatively, the apparatus in whichthe process of the present invention is conducted may be provided withcomponents formed either partially or totally of catalyst material, forexample column internals.

In embodiments of the invention in which metal is present in thereaction mixture as a salt, it may be added to the reaction mixture insalt form and/or solid metal may be added to the reaction mixture, whichthen dissolves in the reaction mixture, forming the salt in situ. Whenpresent in the form of a salt, the catalyst may be added in an amorphousform, crystalline form, an anhydrous form and/or in hydrated form (e.g.ferric chloride hexahydrate). Liquid form catalysts may also beemployed.

Examples of catalysts which may be employed in the dehydrochlorinationstep/s include one or more halides (e.g. chlorides, bromides, fluoridesor iodides) of transition metals such as iron, aluminium, antimony,lanthanum, tin, titanium. Specific examples of catalysts that may beemployed include FeCl₃, AlCl₃, SbCl₅, SnCl₄, TiCl₄.

In embodiments of the invention, the mixture comprises1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane as theplurality of isomers, preferably in a molar ratio of 80:20, 90:10, 93:7,or 95:5. The mixture is subjected to selective dehydrochlorination suchthat 1,1,3,3-tetrachloropropene (HCO-1230za) is produced selectively inpreference to 1,1,2,3-tetrachloropropene (HCO-1230xa), leaving1,1,1,2,3-pentachloropropane largely unconverted. The obtainedchlorinated alkene, 1,1,3,3-tetrachloropropene (HCO-1230za) can beeasily separated from the mixture. The residual mixture, rich in1,1,1,2,3-pentachloropropane can be subjected to treatment steps.

The feed of the mixture comprising C₃ chlorinated alkane isomers and/orcatalyst into the dehydrochlorination zone may be continuous orintermittent, as may extraction of the reaction mixture. In embodiments,the continuous mode is preferred.

One advantage of the processes of the present invention is that desirousresults are obtained whether the dehydrochlorination zone is operated ina continuous or batch process. The terms ‘continuous process’ and ‘batchprocess’ will be understood by those skilled in the art. In embodiments,the continuous mode is preferred.

A further advantage of the present invention is that it enables highpurity chlorinated alkene compounds to be produced without the use ofalkaline hydroxides. This is advantageous as the avoidance of the use ofalkaline hydroxide means that the formation of carbonyl compounds can bereduced or eliminated. Additionally, and unexpectedly, the presentinventors have found that alkaline hydroxide-free dehydrochlorinationsteps are more selective than if alkaline hydroxide is employed.Further, the risk of formation of potentially explosive mixtures ofchlorinated alkenes and alkaline agents can be minimised.

Thus, in embodiments of the present invention, no alkaline hydroxide isadded to the dehydrochlorination zone and/or the reaction mixturepresent in the dehydrochlorination zone is free of alkaline hydroxide.

It will be recognised that, as the reaction proceeds, the first C₃chlorinated alkene will be produced in the dehydrochlorination zone. Inembodiments of the invention, the first C₃ chlorinated alkene isextracted from the dehydrochlorination zone (either directly, or byfirstly extracting reaction mixture from the dehydrochlorination zoneand then extracting the first C₃ chlorinated alkene therefrom, forexample, via distillation). This extraction may be conductedcontinuously or intermittently.

For the avoidance of doubt, where reference is made to ‘continuousextraction’ from the reaction mixture or directly from thedehydrochlorination zone, a strict literal interpretation is notintended; one skilled in the art would recognise that the term is usedto mean that extraction (of the reaction mixture from thedehydrochlorination zone or via direct extraction of the first C₃chlorinated alkene, e.g. via distillation) occurs on a substantiallycontinuous basis, once the dehydrochlorination zone has attained thetarget operating conditions and the reaction mixture has attained asteady state.

Additionally or alternatively, the first C₃ chlorinated alkene can beextracted directly from the reaction mixture in the dehydrochlorinationzone (e.g. via direct distillation), and/or a portion of the reactionmixture can firstly be extracted from the dehydrochlorination zone andthe chlorinated alkene then subsequently extracted from that mixture,remotely from the dehydrochlorination zone. In embodiments wherereaction mixture is extracted from the dehydrochlorination zone, one ormore treatment steps (e.g. a washing step, discussed below) may becarried out prior to and/or following distillation.

In embodiments of the invention, the first C₃ chlorinated alkene may beremoved from the reaction mixture by distillation. Any technique andapparatus known to those skilled in the art may be employed to effectextraction of the first C₃ chlorinated alkene from the reaction mixturein this way. In embodiments of the invention, a distillation column maybe used, for example a rectification column. The reaction mixture maypass (in the case of direct distillation) or be fed into the columnbottom following extraction of the reaction mixture from thedehydrochlorination zone, with the first C₃ chlorinated alkene ofinterest being removed from the top of the column as a liquiddistillate.

For example, in ‘direct distillation’ embodiments, in which the reactionmixture is totally or partially gaseous, for example due to theoperating temperature in the dehydrochlorination zone, the apparatus maybe configured such that the dehydrochlorination zone is in fluidcommunication with the distillation apparatus. In such embodiments, thedistillation apparatus may be coupled to the dehydrochlorination zone.Conveniently, this enables the gaseous first C₃ chlorinatedalkene-containing mixture to pass (or be passed) directly from thedehydrochlorination zone in to the distillation apparatus.Alternatively, the distillation apparatus may be located remotely fromthe dehydrochlorination zone, meaning that the gaseous mixture must beextracted from the dehydrochlorination zone and passed to thedistillation apparatus.

Additionally or alternatively, where the reaction mixture is present inthe dehydrochlorination zone either partly or totally in liquid form, aportion of the liquid reaction mixture may be extracted from thedehydrochlorination zone and passed to distillation apparatus. In suchembodiments, the reaction mixture may be subjected to one or moretreatment steps (e.g. a washing step, discussed below) which precedeand/or follow distillation.

In embodiments in which the first C₃ chlorinated alkene is extractedfrom the reaction mixture by distillation, at least about 50%, at leastabout 60%, at least about 70%, at least about 80%, or at least about 90%by weight of the first C₃ chlorinated alkene present in the reactionmixture subjected to distillation is extracted from that mixture.

Distillation of the first C₃ chlorinated alkene from the reactionmixture can be carried out continuously, semi-continuously orbatch-wise.

A further advantage of the present invention is that thedehydrochlorination reaction produces highly pure gaseous hydrogenchloride from the chlorinated alkene mixture that can be recovered usingroutine techniques, for example by condensation of overhead vapours.

Thus, in embodiments of the invention in which hydrogen chloride isproduced during the dehydrochlorination reaction, the hydrogen chloridemay be extracted. This can be achieved using any equipment and/ortechniques for doing so known to those skilled in the art. For example,if the reaction mixture is subjected to distillation, the distillationapparatus may be provided-with a condenser (e.g. a partial condenser),or a condenser (e.g. a partial condenser) may be provided downstream ofthe reactor apparatus, to enable the removal of hydrogen chloride gas.

In embodiments of the present invention, in which hydrogen chloride gasis extracted from the dehydrochlorination zone or from reaction mixtureextracted therefrom, this may be achieved through the use of deepcooling, i.e. by extracting the gas from the reaction mixture and thencooling it to a temperature of about 0° C. or lower, about −10° C. orlower or about −20° C. or lower.

Cooling apparatus (e.g. a second condenser) may additionally beemployed, e.g. downstream of the first condenser. Arranging theapparatus in this way is advantageous as the first condenser can be usedto condense the bulk of the chlorinated alkene, with the secondcondenser being used to purify the gas by condensing traces of thechlorinated alkene.

The resulting condensate may be recycled back to the dehydrochlorinationzone or optionally used in other associated reaction zones.

Optionally, in order to produce very pure hydrogen chloride gas, a crudehydrogen chloride gas after the first partial condensation together withremaining traces of chlorinated alkene isomer can be subjected achlorination step, preferably by means of UV light, in order to produceheavier chlorinated molecules, which can be easily condensed in thesecond partial condensation and thus separated completely from HCl gas.The resulting condensate containing such heavy chlorinated molecules,may be further processed or treated e.g. in high temperaturechlorinolysis plant or in incineration plant.

Additionally or alternatively, an active carbon adsorption column may beemployed to adsorb traces of chlorinated alkene from hydrogen chloridegas.

Additionally or alternatively, an absorption column may be employed toabsorb hydrogen chloride gas to produce hydrochloric acid solution.

Thus, advantageously, hydrogen chloride extracted as discussed herein ishighly pure and thus can be used as a reactant in upstream or downstreamreactions in the same industrial plant. An example of downstream use isfor the hydrochlorination of glycerol to make monochlorohydrin and/ordichlorohydrin, and subsequently to lead to epichlorohydrin, glycidoland epoxies.

In embodiments of the invention, the extraction of high grade first C₃chlorinated alkene from the dehydrochlorination zone may be achieved bydirect distillation. Additionally or alternatively, reaction mixture mayfirstly be extracted from the dehydrochlorination zone and then(possibly following one or more treatment steps, such as a washing step,discussed below) subjected to distillation to extract high grade firstC₃ chlorinated alkene. Any distillation apparatus or techniqueseffective to extract the first C₃ chlorinated alkene from thedehydrochlorination zone (or reaction mixture extracted from that zone)may be employed.

It has been found by the inventors that, under certain operatingconditions, controlling the mixture within the dehydrochlorination zonesuch that the first C₃ chlorinated alkane isomer does not achieve totalconversion to respective first C₃ chlorinated alkene can prevent theinadvertent and unwanted dehydrochlorination of other C₃ chlorinatedalkane isomers present. Thus, in embodiments of the invention, thereaction conditions in the dehydrochlorination zone are controlled suchthat the total conversion of the first C₃ chlorinated alkane isomer doesnot occur. In such embodiments, the degree of conversion of the first C₃chlorinated alkane isomer to its respective first C₃ chlorinated alkeneis prevented from exceeding about 95%, about 90%, about 80%, about 75%or about 70%.

The degree of conversion of the first C₃ chlorinated alkane isomer toits respective first C₃ chlorinated alkene may be controlled in one ormore of the following ways: i) control of the operating conditions inthe dehydrochlorination zone (e.g. temperature, pressure, agitationspeed, residence time etc. which do not favour higher levels ofchlorinated alkene formation, and/or ii) by controlling the amount ofchlorinated alkane starting material and/or catalyst present in thedehydrochlorination zone. Control of the amount of chlorinated alkaneisomer mixture starting material can be achieved through control of thefeed rate of the starting material into the dehydrochlorination zone.

In embodiments of the invention, residual mixture comprising the firstC₃ chlorinated alkane isomer, one or more additional chlorinated alkaneisomers, optionally the first C₃ chlorinated alkene, and optionallycatalyst may be extracted from the dehydrochlorination zone and/ordistillation apparatus. The molar ratio of the first C₃ chlorinatedalkane isomer:one or more additional chlorinated alkane isomers presentin the reaction mixture extracted from the dehydrochlorination zone maybe in the region of 10:1, 7:1 or 5:1 to about 4:1, 3:1, 2:1, about 1:1or about 0.5:1.

The mixture extracted from the dehydrochlorination zone and/ordistillation apparatus can then be subjected to additional treatmentsteps. In other words, the washing step may be carried out prior to orfollowing any distillation step that is carried out to extract thestream rich in or consisting of the first C₃ chlorinated alkene.

For example, the residual mixture can be subjected to a washing step. Insuch a step, the residual mixture is contacted with an aqueous medium inan aqueous treatment zone which serves to deactivate the catalyst (ifpresent). The residual mixture may also optionally be contacted withacid in the aqueous treatment zone, for example inorganic acid such assulphuric acid, phosphoric acid and/or hydrochloric acid. The acid maybe pure, or may be dilute. The aqueous treatment step has theadvantageous effect of removing certain classes of otherwise problematicimpurities from the residue, especially oxygenated impurities.

In such embodiments, catalyst deactivation can be achieved with only ashort contact time, e.g. about 5, about 10, about 20 or about 30minutes, with water at low temperature is required. For hydrolysis andextraction of chlorinated, oxygenated impurities, the contact time withthe water is longer, e.g. up to about 1 hour, about 2 hours, about 5hours or about 10 hours and/or at a temperature of about 50° C. or less,about 40° C. or less or about 30° C. or less.

Where a dilute acid is employed, this may additionally provide theaqueous medium with which the residual mixture is contacted.Additionally, or alternatively, the aqueous medium may comprise water(in any form, e.g. including steam) which may be added separately intothe aqueous treatment zone.

In embodiments in which acid is added into the aqueous treatment zone,this preferably reduces the pH of the mixture present therein to about 5or lower, about 4 or lower, about 2 or lower or about 1 or lower.

Contacting the residual mixture (which comprises the first C₃chlorinated alkane isomer, one or more additional chlorinated alkaneisomers, optionally the first C₃ chlorinated alkene, and optionallycatalyst with an aqueous medium forms a biphasic mixture.

The biphasic mixture, comprising an aqueous phase and an organic phasemay be formed in the aqueous treatment zone (or in certain embodiments,remotely therefrom), as a result of the presence of both the aqueousmedium and also the predominantly organic residue.

In such embodiments where a biphasic mixture is formed, the organicphase may be extracted from the biphasic mixture using phase separationtechniques and/or equipment known to those skilled in the art. Where thebiphasic mixture is formed in the aqueous treatment zone, the organicphase can be separated from the aqueous phase by the sequentialextraction of the phases from the aqueous treatment zone. The aqueousphase, which contains impurities removed from the residue can be furthertreated.

To maximise phase separation efficiency and thus facilitate extractionof that phase from the biphasic mixture, a haloalkane extraction agentand/or phase separation intensifier (for example, one, some or all ofthe C₃ chlorinated alkane isomers, and/or various alcohols and/orketones) may be added to the aqueous treatment zone, eitherintermittently or continuously, using techniques and/or equipment knownto those skilled in the art. The use of C₃ chlorinated alkane isomers ispreferred as these compounds are part of the product processes and donot require removal using specific separation steps. Optionally, phaseseparation intensifiers such as polar alcohols and/or ketones withboiling points sufficiently different to the chlorinated alkene andchlorinated alkane present in the reaction mixture may be employed. Thedifference in boiling points should be at least 20° C., at least about30° C., at least about 40° C., at least about 50° C. or at least about60° C. Examples of phase separation intensifiers that may be employedinclude aliphatic ketones e.g. acetone and aliphatic alcohols e.g.methanol, ethanol, propanol/s, butanol/s.

In embodiments of the invention, the extracted organic phase may then besubjected to a distillation step in which streams or fractions of thefirst C₃ chlorinated alkene (now highly purified) and, separately, C₃chlorinated alkane isomers are distilled off. A heavy ends residue maybe extracted from the distillation apparatus, optionally filtered andincinerated and/or subjected to high temperature chlorinolysis. Aspecific embodiment in which such a process is operated is presented inExample 7.

The other chlorinated alkane isomers are thus separated from the firstchlorinated alkane isomer, and after distillation, may be used as suchor converted to the corresponding chlorinated alkene, using thedehydrochlorination method disclosed herein or, for example, describedin WO2016/058567.

To increase the stability of chlorinated alkenes produced according tothe processes of the present invention, stabilising compounds can beadded. This is particularly appropriate where the compounds are to bestored or transported in oxygen-containing environments. Examples ofstabilisers include hydroxyl derivatives of aromatics, amines, thiazinesand the like. Where employed, stabilisers may be present in amounts ofabout 1 to 100 ppm or about 2 to about 50 ppm.

Reducing the water content of chlorinated alkene has been found to aidstability. Thus, in embodiments of the present invention, reactionconditions are controlled such that the obtained chlorinated alkeneproduct/s comprise less than about 100 ppm, less than about 50 ppm, orless than about 10 ppm water.

In embodiments of the present invention, the dehydrochlorinationreaction is carried out in the vapour phase, i.e. both the first C₃chlorinated alkane and the first C₃ chlorinated alkene are in gaseousform. In such embodiments, the dehydrochlorination zone may be operatedat a temperature of about 250° C. to about 500° C., about 300° to about425° C. or about 350° C. to about 400° C.

The dehydrochlorination zone may be operated at subatmospheric pressure,atmospheric pressure or superatmospheric pressure.

In embodiments of the invention in which the dehydrochlorinationreaction occurs in the vapour phase, the residence time of the reactionmixture in the dehydrochlorination zone may range from about 0.5 toabout 10 seconds. Additionally or alternatively, a metallic catalyst maybe used, for example one containing iron at levels of 50% by weight orgreater. Examples of catalysts which may be employed in processes of thepresent invention include stainless steels, for example ferritic and/oraustenic steels. Catalysts employed in processes of the presentinvention preferably have an iron content of at least about 50%, atleast about 60%, at least about 70%, at least about 80%, at least about90% or at least about 95% by weight. Pure iron may be employed as acatalyst.

Catalysts may be employed in any form, for example fluid bedarrangements and/or fixed bed arrangements. Additionally oralternatively, components of the dehydrochlorination zone comprising thecatalyst can be employed.

In embodiments in which the dehydrochlorination step is conducted in thevapour-phase, the reaction mixture extracted from thedehydrochlorination zone is typically in the vapour phase. Those hotproduct gases may be condensed using any technique and/or equipmentknown to those skilled in the art, to obtain chlorinated organiccompounds in liquid form.

Regardless of whether dehydrochlorination is carried out in the liquidor vapour phase, the mixture of chlorinated organics, including thefirst C₃ chlorinated alkene and unreacted chlorinated alkane isomers, aswell as impurities may then be subjected to one or morepost-dehydrochlorination treatment steps as discussed above (includingdistillation and/or hydrolysis steps) to obtain the purified first C₃chlorinated alkene.

Any type of reactor known to those skilled in the art may be employed inthe processes of the present invention. Specific examples of reactorsthat may be used to provide a dehydrochlorination zone are columnreactors, tubular reactors, bubble column reactions, plug-flow reactorsand continuously stirred tank reactors.

The process of the present invention may be carried out in a singledehydrochlorination zone or in a plurality of dehydrochlorination zones.Where a plurality of dehydrochlorination zones are employed (forexample, 2, 3, 4, 5, 6 or more dehydrochlorination zones), these may beoperated in sequence (i.e. such that reaction mixture is passed along anumber of dehydrochlorination zones) and/or in parallel.

In embodiments of the invention, where a plurality ofdehydrochlorination zones are employed, optionally in a cascade mode,these may be in the same or different reactors. For example, where aplurality of dehydrochlorination zones are employed, these may beprovided in a plurality (e.g. 1, 2, 3, 4, 5 or more) of reactors (e.g.continuously stirred tank reactors) which may each be configured to haveoptimized operating conditions (e.g. temperature, residence times,etc.).

In an embodiment, a plurality of dehydrochlorination zones may bepresent in a distillation column that may be employed in processes ofthe present invention. In such embodiments, dehydrochlorination may beachieved by reactive distillation, for example where thedehydrochlorination reaction is carried out on trays in a distillationcolumn and/or on packing provided in the column. In embodiments in whichreactive distillation is carried out, the distillation column preferablycomprises a stripping zone in which alkene is separated from alkane. Thestripping zone may be located below the liquid feed.

It has been found that the components of the reaction mixture (e.g.chlorinated alkenes, hydrogen chloride and/or the C₃ chlorinated alkaneisomer starting materials) obtainable from the dehydrochlorinationreaction which is conducted in the processes of the present invention,can unfavourably interact with certain materials. Thus, in embodimentsof the invention, those parts of the dehydrochlorination zone which arein contact with the reaction mixture may have an iron content of about20% or less, about 10% or less or about 5% or less, and/or are formedfrom non-metallic materials, for example enamel, glass, impregnatedgraphite (e.g. impregnated with phenolic resin), silicium carbide and/orplastics materials such as polytetrafluoroethylene, perfluoroalkoxyand/or polyvinylidene fluoride.

In embodiments of the invention, the surfaces of all equipment employedin the processes of the present invention with which chlorinated alkenewill come into contact are formed from suitable materials such as thoseidentified above. One possible exception is where one or more regions ofthe surfaces of the apparatus employed in the processes of the presentinvention are formed of metallic material which is selected to performas a catalyst.

One advantage of the process of the present invention is that desirousresults are obtained whether the chlorination and/or dehydrochlorinationzones are operated in a continuous (steady state) or batchwise process.The terms ‘continuous process’ and ‘batchwise process’ will beunderstood by those skilled in the art.

As can be seen from the disclosure provided herein, the inventiveprocesses of the present invention can be operated in an integratedprocess in a fully continuous mode, optionally in combination with otherprocesses. The process steps of the present invention may employstarting compounds which are converted to highly pure intermediateswhich are themselves further processed to the required targetchlorinated compounds having predetermined ratios to maximize theircommercial value. Those compounds have the requisite purity to beemployed as feedstocks in a range of downstream processes, for examplehydrofluorination conversions.

The processes of the present invention enable product purity levels tobe controlled to attain highly pure target compounds. The processesadvantageously balance high yields, high selectivity and high efficiencywhich is particularly challenging, especially in continuous processes.The processes of the present invention enable high purity chlorinatedalkene compounds to be economically produced on an industrial scale,those compounds having very low levels of a range of impurities.

As will be appreciated from the disclosure herein, use of the inventivechlorination and dehydrochlorination steps discussed provide efficientstreamlined process for producing highly pure, commercially valuable C₃chlorinated compounds. While both of those steps are independentlyinventive, particularly advantageous results are observed when the stepsare operated in sequence.

Thus, according to a further aspect of the present invention, there isprovided a process comprising:

preparing a reaction mixture comprising a plurality of C₃ chlorinatedalkane isomers comprising chlorinating a C₃ chlorinated alkane startingmaterial in a chlorination zone to produce the plurality of C₃chlorinated alkane isomers, the plurality of C₃ chlorinated alkaneisomers each having at least one more chlorine atom than the C₃chlorinated alkane starting material, wherein the concentration of theC₃ chlorinated alkane starting material is controlled such that themolar ratio of the C₃ chlorinated alkane starting material:C₃chlorinated alkane isomers obtained by the chlorination of the C₃chlorinated starting material in the reaction mixture present in thechlorination zone does not exceed about 40:60 (i.e. conversion of the C₃chlorinated alkane starting material does not exceed 60%);subjecting the reaction mixture to one or more first distillation stepsto produce a C₃ chlorinated alkane starting material stream, a pluralityof C₃ chlorinated alkane isomers stream and optionally a single C₃chlorinated alkane isomer stream;subjecting the plurality of C₃ chlorinated alkane isomers stream to aselective dehydrochlorination step in which one of the C₃ chlorinatedalkane isomers, the first C₃ chlorinated alkane isomer, is converted toa respective first C₃ chlorinated alkene without the substantialdehydrochlorination of any of the other of the plurality of C₃chlorinated alkane isomers, andseparating the first C₃ chlorinated alkene from the mixture prepared inthe dehydrochlorination step.

For the avoidance of doubt, the chlorination, distillation,dehydrochlorination and separation steps employed in this aspect of thepresent invention may be operated using conditions, apparatus, reagents,catalysts, etc. as presented in connection with analogous steps herein.

In embodiments of this aspect of the present invention, no additionaldistillation step aside from that recited above is performed followingthe chlorination step and prior to the dehydrochlorination step.

Separation of the first C₃ chlorinated alkene is preferably achievedusing distillation techniques, for example those as discussed herein.

As an example of a process of this aspect of the invention, a mixture of1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane may beproduced with high levels of purity by chlorinating1,1,1,3-tetrachloropropane. The mixture is then distilled to provide:

-   -   a mixture of 1,1,1,3,3-pentachloropropane and        1,1,1,2,3-pentachloropropane with a higher ratio of        1,1,1,3,3-pentachloropropane:1,1,1,2,3-pentachloropropane than        in the reaction mixture present in the chlorination zone,    -   a stream of unreacted 1,1,1,3-tetrachloropropane starting        material, which can be recycled back to the chlorination zone.    -   pure 1,1,1,2,3-pentachloropropane which is useful in the        production of downstream chlorinated alkenes and/or        fluorocarbons, and    -   heavy ends to be further treated for example by high temperature        chlorinolysis or incineration.

The mixture of pentachloropropane isomers with the increased ratio1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane (e.g.93:7) may then be selectively dehydrochlorinated under conditions suchthat only the 1,1,1,3,3-pentachloropropane is converted to itscorresponding alkene, 1,1,3,3-tetrachloro-1-propene, in the presence of1,1,1,2,3-pentachloropropane.

This mixture of 1,1,3,3-tetrachloro-1-propene and1,1,1,2,3-pentachloropropane (with low levels of unconverted1,1,1,3,3-pentachloropropane) is successfully, and more easily,separated by distillation to provide high purity1,1,3,3-tetrachloro-1-propene (1230za) and a mixture of unconverted1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane, which canthen be recycled to the post-chlorination distillation step oralternatively to chlorination step. The isolated 1230za can then be usedas a feedstock for producing the 1-chloro-3,3,3-trifluoropropene blowingagent.

The processes of the present invention are particularly advantageous asthey enable highly pure chlorinated alkane isomer mixes and alkenes tobe produced using simple and straightforward techniques and equipmentwith which one skilled in the art would be familiar.

Examples of highly pure compounds with controlled impurity profiles thatcan be prepared according to the integrated, streamlined and optionallycontinuous processes of the present invention (from ethylene and withoutthe use of toxic vinyl chloride) include: 1,1,3,3-tetrachloropropene,which is useful for the production of blowing agents 1233zd1,1,1,2,3-pentachloropropane which is useful for conversion to highlypure 1230xa or for 1234yf synthesis.

As those skilled in the art will appreciate, previous methods forproducing a C₃ plurality of chlorinated alkanes and alkenes involveseveral separate steps and require the use of a wider range of startingfeedstocks. There would be variability in production of above desiredchlorinated products. In contrast, the processes of the presentinvention can achieve the production of a range of commercially valuableproducts from a single production line using the minimum number ofstarting materials. Further, the processes advantageously provide rawmaterials that are capable for use, without extensive treatment in thefollowing processes:

-   -   a chlorinolysis process, utilising heavy by products from the        distillation residue stream obtainable from the        post-chlorination distillation step discussed above to produce        the useful starting feedstock carbon tetrachloride CTC,    -   the production of chlorinated alkenes from the single isomer        stream obtainable from the post-chlorination distillation step        discussed above a C₃ chlorinated feedstock process producing        1,1,1,2,3-pentachloropropane, 1,1,3,3-tetrachloropropene and        1,1,2,3-tetrachloropropene, and    -   the utilisation of the hydrogen chloride gas in downstream        processes, e.g. HCl electrolysis, oxychlorination, the        production of dichloropropanol from glycerol, epichlorohydrin        from glycerol, and pure hydrochloric acid.

In embodiments of the invention, the processes of the invention can beused to produce high purity chlorinated alkane compositions, e.g.1,1,1,2,3-pentachloropropane. Thus, according to a further aspect of thepresent invention, there is provided a composition comprising a C₃chlorinated alkane compound obtainable from the processes discussedherein which comprises:

-   -   The C₃ chlorinated alkane in amounts of at least about 95%, at        least about 99.5%, at least about 99.7%, at least about 99.8%,        at least about 99.9%, or at least about 99.95%, and one or more        of the following:    -   Oxygenated organic compounds in amounts of less than about 500        ppm, about 250 ppm or less, about 100 ppm or less, about 50 ppm        or less, or about 10 ppm or less,    -   Isomers of the chlorinated alkane of interest in amounts of less        than about 500 ppm, about 250 ppm or less, or about 100 ppm or        less,    -   Non-isomeric alkane impurities in amounts of less than about 500        ppm, about 250 ppm or less, or about 100 ppm or less,    -   Chlorinated alkenes in amounts of less than about 500 ppm, about        250 ppm or less, about 100 ppm or less, or about 50 ppm or less,    -   Water in amounts of less than about 500 ppm, about 250 ppm or        less, about 100 ppm or less or about 50 ppm or less,    -   Inorganic compounds of chlorine in amounts of about 100 ppm or        less, about 50 ppm or less, about 20 ppm or less or about 10 ppm        or less,    -   Brominated organic compounds in amounts of about 100 ppm or        less, about 50 ppm or less, about 20 ppm or less or about 10 ppm        or less, and/or    -   Iron in amounts of about 100 ppm or less, about 50 ppm or less,        about 20 ppm or less, about 10 ppm or less or about 5 ppm or        less.

In embodiments of the invention, the processes of the invention can beused to produce high purity chlorinated alkene compositions, e.g.1,1,3,3-tetrachloropropene, 2,3,3,3-tetrachloropropene,1,1,2,3-tetrachloropropene or 1,3,3,3-tetrachloropropene. Thus,according to a further aspect of the present invention, there isprovided a composition comprising a C₃ chlorinated alkene obtainablefrom the processes discussed herein which comprises:

about 95% or more, about 97% or more, about 99% or more, about 99.2% ormore about 99.5% or more or about 99.7% or more of the C₃ chlorinatedalkene,

less than about 50000 ppm, less than about 25000 ppm, less than about20000 ppm, less than about 10000 ppm, less than about 5000 ppm, lessthan about 2000 ppm, less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, or less than about 100 ppm of chlorinatedalkane starting material,

less than about 50000 ppm, less than about 25000 ppm, less than about20000 ppm, less than about 10000 ppm, less than about 5000 ppm, lessthan about 2000 ppm, less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, or less than about 100 ppm of chlorinated C₄alkanes and C₄ alkenes less than about 1000 ppm, less than about 500ppm, less than about 200 ppm, or less than about 100 ppm of chlorinatedC₅₋₆ alkane impurities,

less than about 5000 ppm, 1000 ppm, less than about 500 ppm, less thanabout 200 ppm, or less than about 100 ppm of chlorinated alkeneimpurities (i.e. chlorinated alkenes other than the compound ofinterest),

less than about 1000 ppm, less than about 500 ppm, less than about 250ppm, or less than about 100 ppm of oxygenated organic compounds,

less than about 500 ppm, less than about 200 ppm, less than about 100ppm, less than about 50 ppm, less than about 20 ppm, less than about 10ppm or less than about 5 ppm metal, and/or

less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm water.

According to a further aspect of the present invention, there isprovided a process for preparing a hydrofluoroolefin orhydrochlorofluoroolefin comprising the step of providing a highly purechlorinated alkene composition as discussed above, or as obtained fromthe dehydrochlorination process of the present invention, and convertingthe chlorinated alkene to a hydrofluoroolefin orhydrochlorofluoroolefin.

This conversion may be achieved through any process known to thoseskilled in the art. In embodiments of the invention, the conversion iscarried out in a hydrofluorination plant.

In preferred embodiments, the chlorinated alkene present as theprincipal component of the composition has a dichlorinated terminalcarbon atom, for example 1,1,3,3-tetrachloropropene and thehydrofluoroolefin or hydrochlorofluoroolefin preferably has atrifluorinated terminal carbon atom, for example2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene or1-chloro-3,3,3-trifluoropropene.

The processes of the present invention also permit the preparation ofhighly pure combinations of C₃ chlorinated alkane isomers which findutility in downstream reactions.

Additionally, the processes of the present invention can employ suchcombinations as feedstocks in commercially viable processes.

Thus, according to a further aspect of the present invention, there isprovided a composition (which may or may not be obtainable from theprocesses of the present invention) comprising a plurality of C₃chlorinated alkane isomers, for example, 1,1,1,2,3-pentachloropropaneand 1,1,1,3,3-pentachloropropane or 1,1,1,2,3-pentachloropropane and1,1,2,2,3-pentachloropropane, at a purity (i.e. a content as percentageby weight) of about 95% or higher, about 97% or higher, about 99% orhigher, about 99.5% or higher, about 99.7% or higher about 99.8% orhigher, or about 99.9% or higher of the plurality of C₃ chlorinatedalkane isomers and preferably further comprises:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about 10 ppm or        less than about 5 ppm of under chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        over chlorinated impurities,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 100 ppm or less than about ppm of        chlorinated alkene compounds,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm or less than about 5        ppm of compounds having a different number of carbon atoms than        the isomers,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm less than about 5        ppm, or less than about 2 ppm of oxygenated organic impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 10 ppm or less than about 5 ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 10 ppm or less than about 5 ppm water.

According to a further aspect of the present invention, there isprovided a composition (which may or may not be obtained from theprocesses of the present invention) comprising a C₃ chlorinated alkaneoptionally selected from 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane and a C₃ chlorinated alkene optionallyselected from 1,1,2,3-tetrachloro-1-propene,1,1,3,3-tetrachloro-1-propene, and 1,3,3,3-tetrachloro-1-propene, the C₃chlorinated alkane and the C₃ chlorinated alkene together having apurity of about 95% or higher, about 97% or higher, about 99% or higher,about 99.5% or higher, about 99.7% or higher, about 99.8% or higher orabout 99.9%, the composition further comprising:

-   -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about ppm or        less than about 5 ppm of C₃ chlorinated alkane compounds        comprising less chlorine atoms than the first C₃ chlorinated        alkane,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        C₃ chlorinated alkane compounds comprising more chlorine atoms        than the C₃ chlorinated alkane,    -   less than about 5000 ppm, less than about 2000 ppm, less than        about 1000 ppm, less than about 500 ppm, less than about 200        ppm, less than about 100 ppm, less than about 50 ppm, less than        about 20 ppm, less than about 10 ppm or less than about ppm of        chlorinated alkene compounds other than the C₃ chlorinated        alkene compound,    -   less than about 10000 ppm, less than about 5000 ppm, less than        about 2000 ppm, less than about 1000 ppm, less than about 500        ppm, less than about 200 ppm, less than about 100 ppm, less than        about 50 ppm, less than about 20 ppm, less than about ppm or        less than about 5 ppm of compounds having a different number of        carbon atoms than the C₃ chlorinated alkane compound,    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm,        less than about 20 ppm, less than about ppm less than about 5        ppm, or less than about 2 ppm of oxygenated organic impurities,    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm, less than about 20 ppm,        less than about 10 ppm or less than about ppm metal, and/or    -   less than about 100 ppm, less than about 50 ppm, less than about        20 ppm, less than about 10 ppm or less than about 5 ppm water.

As confirmed above, the compositions of the present invention, and theproducts obtained from the processes of the present invention,advantageously benefit from a combination of very high purity andacceptable impurities. This makes them well-suited for use in downstreamreactions, particularly in the preparation of hydrofluorinated orhydrochlorofluorinated alkane or alkene compounds.

Thus, according to a further aspect of the present invention, there isprovided the use of the compositions described herein, or the productsof the processes described herein in the preparation of fluorinatedalkane or alkene compounds. In embodiments of this aspect of the presentinvention, the fluorinated alkane or alkene compound may have atrifluorinated terminal carbon atom, for example2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene(HFO-1234ze), 1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zd),2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db),2-chloro-2,3,3,3-tetrafluoropropane (HCFC-244bb),1,1,1,2,2-pentafluoropropane (HFC-245cb),1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa) or1,1,1,3,3-pentafluoropropane (HFC-245fa).

In a preferred aspect of this aspect of the invention, thedehydrochlorination step of the present invention results in theproduction of a high purity composition comprising1,1,3,3,-tetrachloropropene, for example that disclosed above, which isused in the direct or indirect production of hydrofluoroolefins orhydrochlorofluoroolefins, preferably those including trifluorinatedterminal carbon atoms such as 1-chloro-3,3,3-tetrafluoropropene,2,3,3,3-tetrafluoropropene and/or 1,3,3,3-tetrafluoropropene.

The invention is further illustrated in the following Examples in whichreference is made to the following figures:

FIG. 1 is a schematic drawing of an arrangement that may be employed inthe processes of the present invention to achieve chlorination of a C₃chlorinated alkane starting material.

FIG. 2 is a schematic drawing of an arrangement that may be employed inthe processes of the present invention to distill valuable productstreams from a mixture comprising a plurality of C₃ chlorinated alkaneisomers.

FIGS. 3 and 4 are schematic drawings of arrangements that may beemployed in the processes of the present invention for selectivelydehydrochlorinating one isomer present in a plurality of C₃ chlorinatedalkane isomers.

FIG. 5 is a schematic drawing of an arrangement that may be employed inthe processes of the present invention in which a mixture comprising aC₃ chlorinated alkene may be subjected to aqueous treatment.

FIG. 6 is a schematic drawing of an arrangement that may be employed inthe processes of the present invention to distill valuable productstreams from a mixture comprising a C₃ chlorinated alkene.

EXAMPLES

Glossary: in following tables, the following nomenclature is used Shortterm Compound

Short term Compound 1113-TeCPa 1,1,1,3-tetrachloropropane 1123-TeCPe1,1,2,3-tetrachloropropene 1133-TeCPe 1,1,3,3-tetrachloropropene1333-TeCPe 1,3,3,3-tetrachloropropene 11133-PCPa1,1,1,3,3-pentachloropropane 11123-PCPa 1,1,1,2,3-pentachloropropane111333-HCPa 1,1,1,3,3,3-hexachloropropane 111233-HCPa1,1,1,2,3,3-hexachloropropane 111223-HCPa 1,1,1,2,2,3-hexachloropropane

Example 1 Chlorination of 1,1,1,3-Tetrachloropropane to Produce aMixture of Pentachloropropanes

Chlorination was carried out as shown in FIG. 1 in a batch bubble columnglass reactor (2) with external cooling circulations (3,7). The reactorwas equipped with 250 W medium pressure mercury lamp immersed usingquartz tube inside the column reactor. The cooling medium for coolers(4,8) was ethylene glycol solution. Gaseous chlorine (1) was introducedat the reactor bottom using a set of nozzles and liquid feedstock wasinitially filled using line (6). The temperature in the reactor wascontrolled to about 25° C.; the pressure in the reactor was atmospheric.The vent gas (10), hydrogen chloride with trace amounts of chlorine, wasled to a caustic scrubber and the caustic was regularly analyzed forNaOCl and alkalinity in order to check HCl formation and chlorine lossvia vent gas.

460.7 kg of 1,1,1,3-Tetrachloropropane with a purity of 98.4% wasinitially filled into the chlorination reactor. Chlorine gas (83.1 kg)was introduced into the chlorination zone at a feeding rate of 8 kg/h.The 1,1,1,3-tetrachloropropane starting material was produced using theprocess and purity profile as described in WO2016/058566.

The amount of hydrogen chloride produced was 39.8 kg and the loss ofchlorine was almost zero. The molar ratio ofchlorine:1,1,1,3-tetrachloropropane was 47%. After about 10 hours thereaction was stopped and 502.7 kg of produced reaction mixture wasanalyzed by GC to provide the following results:

Compound Amount (wt. %) 1113-TeCPa 53.98% 11133-PCPa 34.93% 11123-PCPa9.31% 111333-HCPa 0.74% 111233-HCPa 0.58% 111223-HCPa 0.34%

Calculated selectivity towards 11133PCPa was 79%.

As can be seen, control of the molar ratio of the starting material(1,1,1,3-tetrachloropropane):chlorinated alkane isomers(1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane) waslimited to 59:41 which advantageously prevented the formation of highamounts of over chlorinated impurities.

Example 2 Purification of the Reaction Mixture from Example 1

As shown in FIG. 2, a batch vacuum glass distillation column (4) withaccessories (5, 6, 7, 8, 9) was filled with plastic rings equal to about25 theoretical stages efficiency. The vacuum in the column was set onappropriate level to keep the bottom of the boiler (2) temperature below110° C.

35.164 kg of reaction mixture was extracted from the reactor used inExample 1 and was initially filled to the column boiler (2) via line(1). Using reflux ratio of about 5 in sum, four fractions as distillatesF1 (10.1), F2 (10.2), F3 (10.3), F4 (10.4.) and one fraction F5(DR) asdistillation residue (3) were collected. The composition and mass of thefractions were following:

Distillation Feed F1 F2 F3 F4 F5(DR) Mass kg 35.164 18.411 13.289 2.2060.181 0.476 1113-TeCPa % 53.98 97.93 0.12 0.00 0.00 0.00 11133-PCPa %34.93 1.80 92.95 0.02 0.01 0.00 11123-PCPa % 9.31 0.00 6.90 99.68 68.290.81 111333-HCPa % 0.74 0.00 0.22 28.76 26.05 111233-HCPa % 0.58 0.1545.72 111223-HCPa % 0.34 0.05 26.02

means concentration less than 0.005% wt., blank cell means notdetectable=less than 1 ppm.

The following recycling scheme was then applied:

Fraction F1: unreacted starting material stream, to be recycled to thechlorination Example 1Fraction F2: chlorinated alkane isomers product stream, to be used asfeedstock for next process step (see Examples 3, 4, 5)Fraction F3: single isomer product stream (second main product11123-PCPa), to be used as feedstock for downstream processes e.g. asprecursor of chlorinated or fluorinated alkenes.Fraction F4: to be recycled to the next distillation trial according tothis Example 2 in order to built up concentration of 111333-HCPaimpurity and after that to be further treated using e.g. hightemperature chlorinolysis process to recover chlorine value or to beincineratedFraction F5 distillation residue, to be further treated using e.g. hightemperature chlorinolysis process to recover chlorine value or to beincinerated

Considering the sum of 1,1,1,3,3- and 1,1,1,2,3-pentachloropropanesobtained, the calculated yield of distillation (without recyclingscheme) is 99.45%

As can be seen, from the initial mixture which was subjected todistillation (comprising 1,1,1,3-tetrachloropropane starting material,1,1,1,2,3-pentachloropropane, 1,1,1,3,3-pentachloropropane andover-chlorinated impurities specifically), the1,1,1,3-tetrachloropropane feedstock is separated as a major fraction F1and sent back to the chlorination reaction zone. Fraction F2 is amixture of 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane, wherein the content of1,1,1,2,3-pentachloropropane is reduced (owing to the extraction of highpurity 1,1,1,2,3-pentachloropropane as fraction F3). Fraction F3 is highpurity 1,1,1,2,3-pentachloropropane which is isolated as a usefulproduct in downstream processes. Minor fractions F4 and F5 areretrieved, and are either recycled or sent for recovery of chlorinecontent for example in a high temperature chlorinolysis process.

The preparation of fraction F2 of 1,1,1,3,3-pentachloropropane and1,1,1,2,3-pentachloropropane was configured to have greater selectivitytowards the 1,1,1,3,3-pentachloropropane isomer as the end product ofinterest in this synthesis is its corresponding alkene,1,1,3,3-tetrachloropropene (1230za) the production of which is discussedbelow. Importantly, fraction F2 is free of starting alkane material(1,1,1,3-tetrachloropropane, 250fb) as 250fb can form1,1,3-trichloropropene in the downstream dehydrochlorination steps.Separation of 1,1,3-trichloropropene from the desired1,1,3,3-tetrachloropropene is problematic as 1,1,3-trichloropropene is amore reactive chlorinated alkene and it can be a catalyst poison fordownstream hydrofluorination processes, for example the conversion of1,1,3,3-tetrachloropropene to e.g. 1,1,1-trifluoro-3-chloro-1-propene(HFCO-1233zd), 1,1,1,3-tetrafluoro-1-propene (HFO-1234ze),1,1,1,3,3-pentafluoropropane (HFC-245fa) and mixtures thereof.

Example 3 Highly Selective Dehydrochlorination of Mixture of 1,1,1,3,3-and 1,1,1,2,3-Pentachloropropanes

Fraction F2 (10.2) from Example 2 was fed into a continuous stirred tankglass reactor (2) as shown in FIG. 3. The reactor (2) consisted of afour neck glass flask equipped with a magnetic stirrer, thermometer,back cooler (4), feed and discharge pipes and hot oil heating bath. Thefeedstock (1) consisted of fraction F2 and about 100 ppm (based on thefeedstock) added catalyst (FeCl₃). Such a liquid feedstock wascontinuously fed by a dosing pump into the reactor. The formed HCl gas(3) was cooled down by means of a back cooler/condenser (4) and then (6)absorbed in an absorption column into the water to check the rate of HClformation. The reaction mixture (7) was continuously automaticallyextracted from the reactor via a cooler (8) to the glass collectionvessel (9) to keep the liquid level in the reactor on the constantvalue. Temperature of reaction was about 102° C., temperature of thesubcooled reaction mixture was less than 20° C. and reaction pressurewas atmospheric. The calculated mean residence time was 2:09 hour.

4230 g of fraction F2 from Example 2 with added catalyst wascontinuously fed into the reactor at a rate of 145 g/h. Then, in sum,450 g HCl was produced and absorbed in the absorption column. 3724 g ofproduct mixture was extracted and analyzed by GC to provide thefollowing results:

Feed Reaction mixture 1333-TeCPe (%) 0.10 1133-TeCPe (%) 0.02 69.581123-TeCPe (%) 0.20 11133-PCPa (%) 92.95 22.96 11123-PCPa (%) 6.90 7.00

Basic Parameters of Reaction Steps:

Reactor 1 Mean residence time 2:09 h Temperature 102° C. Pressure atm.Calculated 11133-PCPa conversion 75.3% Calculated selectivity 1133-towards 1123-TeCPe 99.7%

As can be seen from this example, the selectivity of thedehydrochlorination step in favour of the production of1,1,3,3-tetrachloropropene was very high, at 99.7%

Example 4 Highly Selective Catalytic Dehydrochloration of the Mixture ofPentachloropropanes from Example 2

This dehydrochlorination step was carried out in a similar manner asdescribed in Example 3 above, but in series or cascade of threecontinuously stirred tank glass reactors (2, 8, 14) as shown in FIG. 4.The liquid reaction mixture (7) was continuously extracted via line (7)from first reactor (2) and then fed to the second reactor (8), and thenfrom the second reactor to the third reactor (14) via line (13).

From the third reactor, the said liquid reaction mixture (19) wasextracted via the cooler (20) and collected in a glass flask. Eachreactor was equipped with the same accessories as in Example 3. Catalyst(FeCl₃) was added in the amount of 100 ppm only in the liquid feed (1)to the first reactor. Samples of reaction mixture were analyzed by GCupon extraction from each reactor. The formed hydrogen chloride gas (3,9, 15) from each reactor was separately cooled down by means of a backcooler/condenser (4, 10, 16) and then (6, 12, 18) absorbed in separatedabsorption columns into the water to check the rate of HCl formation(and thus relate to the conversion) in each reactor. The operatingtemperature in the reactors was 101, 100 and 103° C., respectively. Thetemperature of the subcooled reaction mixture was less than 20° C. andthe pressure was always atmospheric.

5301 g of mixture of fraction 2 (the chlorinated alkane isomers streamcomprising pentachloropropanes) from Example 2 with added catalyst wascontinuously fed into the first reactor at a rate of 552 g/h. 679 ghydrogen chloride was produced and absorbed in three absorption columnsand 4573 g of product mixture was extracted from the third reactor. Thisproduct mixture was analyzed by GC to provide the following results:

Feed Reactor 1 Reactor 2 Reactor 3 1333-TeCPe (%) 0.11 0.13 0.061133-TeCPe (%) 0.02 48.26 67.56 76.38 1123-TeCPe (%) 0.07 0.12 0.1511133-PCPa (%) 92.95 44.27 24.89 16.12 11123-PCPa (%) 6.90 7.14 7.167.12

Basic Parameters of Reaction Steps:

Reactor 1 Reactor 2 Reactor 3 Mean residence time 0:29 h 0:31 h 0:35 hTemperature 101° C. 100° C. 103° C. Pressure atm. atm. atm. Calculated11133-PCPa cumulative 52.4% 73.2% 82.7% conversions Calculatedcumulative selectivity 99.9% 99.8% 99.8% 1133- towards 1123-TeCPe

Examples 3 and 4 illustrate highly selective catalyticdehydrochlorination steps using a mixture of pentachloropropane isomersas a starting material. The isomeric ratio of1,1,1,3,3-pentachloropropane to 1,1,1,2,3-pentachloropropane of 93:7 wasachieved by the efficient distillation of the reaction mixture afterchlorination which results in a single isomer stream being obtainedwhich is rich in 1,1,1,2,3-pentachloropropane, as well as a plurality ofC₃ chlorinated alkane isomer stream being obtained having the increasedisomeric ratio of1,1,1,3,3-pentachloropropane:1,1,1,2,3-pentachloropropane. Asdemonstrated, dehydrochlorination can be carried out either in onereactor as in Example 3 or in series of three reactors as shown inExample 4, where selectivity of 1,1,3,3-tetrachloropropene over1,1,2,3-tetrachloropropene of 99.8% was achieved by higher feedstockconversion rate and lower residence time.

Example 5 Selective Dehydrochlorination of the Pentachloropropane IsomerMixture Obtained in Example 1

Highly selective catalytic dehydrochlorination of mixture ofpentachloropropanes was carried out in similar manner as in Example 4.However, a different feedstock was used, comprising a plurality ofpentachloropropane isomers in the ratio in which they were produced inExample 1.

5879 g of the mixed pentachloropropane isomer feedstock (isomer ratio of11133:11123-PCPa=78.95:20.97) with added catalyst was continuously fedinto the first reactor at a rate of 920 g/h. 631 g of hydrogen chloridewas produced and absorbed in three absorption columns. 5194 g of productmixture was obtained from the third reactor and analyzed by GC toprovide the following results:

Feed Reactor 1 Reactor 2 Reactor 3 1333-TeCPe (%) 0.11 0.07 0.081133-TeCPe (%) 0.02 47.87 61.43 66.55 1123-TeCPe (%) 0.29 0.43 0.5111133-PCPa (%) 78.95 30.26 16.58 11.26 11123-PCPa (%) 20.97 21.24 21.2021.25

Basic Parameters of Reaction Steps:

Reactor 1 Reactor 2 Reactor 3 Mean residence time 0:17 h 0:18 h 0:20 hTemperature 100° C. 101° C. 101° C. Pressure atm. atm. atm. Calculated11133-PCPa cumulative 61.7% 79.0% 85.7% conversions Calculatedcumulative selectivity 99.4% 99.3% 99.2% 1133- towards 1123-TeCPe

Example 5 illustrates a further highly selective dehydrochlorinationstep.

Selectivity of the desired C₃ chlorinated alkene of 99.2% was achieved.

Isomer Selectivity Comparison Table:

Example 3 Example 4 Example 5 TeCPe isomer selectivity 99.7% 99.8% 99.2%11123-PCPa conversion (loss) 3.32% 2.58% 2.95%

Example 6 Aqueous Treatment of C₃ Chlorinated Alkene-Containing Mixtures

The reaction mixtures obtained from the dehydrochlorination stepsperformed in Examples 3, 4 and 5 were purified using a water treatmentstep carried out in a batch stirred glass reactor equipped with a highrotation-speed stirrer and temperature control system as shown on FIG.5. 2% hydrogen chloride solution was mixed with distilled water (2).Cold mixture obtained from the dehydrochlorination steps (1) was mixedwith the acidic solution in a 1:1 ratio and the resulting mixturestirred for about 5 hours. This aqueous treatment results indeactivation of catalytic system and hydrolysis and removal ofmedium-polar or polar compounds, particularly oxygenated, chlorinatedbyproducts. This treatment is conducted at a temperature of about 20-25°C. and preferably not more than about 50° C. After stirring, the stirrerwas stopped and mixture was separated into two layers—an upper aqueouslayer and a lower organic layer. The lower layer was then extracted fromthe reactor (4) and dried using calcium chloride. The dried organiclayer was then subjected to the distillation step in Example 7.

Example 7 Distillation of Aqueous Treated C₃ Chlorinated AlkeneContaining Mixture

Following the aqueous treatment step of Example 6, purification of themixture obtained in Example 4 was efficiently carried out in a batchvacuum glass distillation column (4) with accessories as shown in FIG.6.

The column was filled with ceramic Berl saddles equal to about 30theoretical stages efficiency. The vacuum was set on appropriate levelto keep the bottom of the boiler at a temperature below 110° C. 6430 gof the chlorinated alkene-containing mixture (1) was fed to the columnboiler (2). Three fractions as distillates F1(10.1), F2(10.2), F3(10.3)and one fraction F4(DR) as distillation residue were collected (3) usinga reflux ratio of about 5. The composition and mass of the fractionswere as follows:

feed F 1 F 2 F 3 F 4(DR) mass (g) 6430 326 3905 435 1461 lights (%) 0.121.53 0.05 0.26 0.01 1333-TeCPe (%) 0.05 0.74 0.56 0.05 ND 1133-TeCPe (%)75.22 97.66 99.36 66.90 0.14 1123-TeCPe (%) 0.14 0.01 0.01 2.23 0.0411133-PCPa (%) 17.26 ND <0.005 30.08 67.38 11123-PCPa (%) 7.15 ND ND0.00 32.08

The fractions were then processed as follows:

Fraction F1: was recycled for use in subsequent distillation stepscorresponding to those carried out in this Example 7 in order to buildup the concentration of light ends which can subsequently be purged andfurther treated using e.g. high temperature chlorinolysis process orincineration

Fraction F2 is the main product stream comprising the target chlorinatedalkene (1,1,3,3-tetrachloropropene at high purity) with acceptably lowlevels of 1,1,2,3-tetrachloropropene. This product stream can be used asa feedstock in downstream processes e.g. as precursor ofhydrofluorinated alkenes.

Fraction F3: was recycled for use in subsequent distillation stepscorresponding to those carried out in this example in order to build upthe concentration of 1,1,2,3-tetrachloropropene and other impuritieswhich can subsequently be treated using e.g. high temperaturechlorinolysis process or incineration, or which can be fed back for usein a chlorination step of the present invention, e.g. that described inExample 1.

Fraction F4(DR) was recycled to the distillation step of Example 2.

Calculated yield of distillation (without recycling scheme): 80.2%

Example 8 Influence of Molar Ratio of C₃ Chlorinated Alkane StartingMaterial:C₃ Chlorinated Alkane Isomer in Reaction Mixture DuringChlorination Step

Chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out in a glass batch stirred reactor.

The reactor was equipped with a 125 W medium pressure mercury lamp.Temperature in the reactor was maintained at about 12° C. and thepressure in the reactor was atmospheric. The vent gas was bubbled into acaustic scrubber and this caustic was regularly analysed with respect toalkalinity in order to check the amount of hydrogen chloride formation.Chlorine gas was introduced into the reactor via a glass dip pipe withnozzle and was totally consumed in the reactor.

504.4 g of 1,1,1,3-tetrachloropropane starting material with a purity of99.9% was initially filled to the reactor. 198 g of chlorine waslikewise fed at a rate of 33 g per hour. Samples from the reactor weretaken regularly and were analyzed by GC to provide the followingresults:

Amount of chlorine based on stoichiometry ratio 20% 40% 60% 80% 100%Ratio of 1113-TeCPa starting 82:18 64:36 45:55 28:72 12:88 materialtowards all PCPa isomers Ratio of 11123-PCPa towards all 19.2 19.3 19.318.7 17.7 PCPa isomers (%) Ratio of HCPa towards all PCPa 1.0 2.3 4.47.7 15.0 isomers (%) Ratio of 111333-HCPa towards 2.1 5.1 10.2 18.9 39.911123-PCPa (%)

From the above results, it is observed that molar ratio betweenfeedstock 1,1,1,3-tetrachloropropane and the isomeric product mixturesignificantly influences the formation of unwanted hexachloropropanecompounds and thus yield. The undesired 1,1,1,3,3,3-hexachloropropane,which has boiling point close to 1,1,1,2,3-pentachloropropane, isdifficult to remove and is also extremely reactive in the presence oftrace of metals. As is apparent from the data shown here, control of theconversion of the starting material prevents formation of theseproblematic impurities.

Thus to minimise production of problematic over chlorinated impurities,the conversion of the feedstock chloroalkane to the productchloropropanes, represented by the molar ratio between the feedstockchloroalkane and product chloropropanes, should be kept such that itdoes not exceed about 40:60, and more advantageously does not exceedabout 60:40.

Example 9 Influence of Reaction Temperature During Chlorination

A series of chlorinations of 1,1,1,3-tetrachloropropane at a range oftemperatures to produce a mixture of 1,1,1,3,3-pentachloropropane and1,1,1,2,3-pentachloropropane were carried out in a glass batch stirredreactor. The reactor was equipped with a 125 W medium pressure mercurylamp. The operating temperature in the reactor was maintained at 10° C.,25° C., 50° C., 60° C., 95° C. and 115° C. Pressure in the reactor wasatmospheric. The vent gas was bubbled into a caustic scrubber and thecaustic was regularly analysed for the alkalinity in order to checkhydrogen chloride formation. Chlorine was introduced into the reactorvia glass dip pipe with nozzle and was totally consumed in the reactor.

600 g of 1,1,1,3-tetrachloropropane with a purity of 99.9% was initiallyfilled into the reactor. Chlorine was fed in to the reaction in aquantity equal to 60% by stoichiometry at a feeding rate of 100 gramsper hour. The reaction mixture after completion was sampled from thereactor and was analysed by GC. The GC analytical results and kineticstudy results are shown in the following tables:

Example No. 9.1 9.2 9.3 9.4 9.5 9.6 Reaction temperature 10° C. 25° C.50° C. 60° C. 95° C. 115° C. 1113-TeCPa (%) 44.13 42.61 43.69 43.5647.18 44.11 11133-PCPa (%) 42.15 43.20 41.77 41.31 37.93 39.6311123-PCPa (%) 10.19 10.98 10.98 11.42 10.26 10.99 111333-HCPa (%) 0.971.11 1.17 1.16 1.38 1.41 111233-HCPa (%) 0.76 0.88 0.99 1.03 1.51 1.66111223-HCPa (%) 0.45 0.49 0.51 0.51 0.39 0.26 Other (%) 1.36 0.74 0.891.00 1.35 1.94 Reaction temperature 10° C. 25° C. 50° C. 60° C. 95° C.115 Ratio of 11123-PCPa towards 19.47 20.27 20.82 21.66 21.29 21.71 allPCPa isomers (%) Ratio of HCPa isomers 4.15 4.56 5.05 5.12 6.81 6.58towards PCPa isomers (%) Ratio of all heavies incl. 4.24 4.57 5.10 5.147.52 8.07 HCPa isomers towards PCPa isomers (%)

The above results demonstrate that reaction temperature in thechlorination zone influences the rate of formation of thehexachloropropanes and thus yield. The pentachloropropane isomericselectivity remains relatively stable across the range of temperatures(i.e. surprisingly, selectivity cannot be controlled by the temperaturein this particular). Accordingly, for the efficient synthesis of1,1,1,3,3-pentachloropropane modest operating temperatures arepreferred, e.g. below 60° C. or more preferably below 40° C.

Example 10 Continuous Chlorination of 1,1,1,3-Tetrachloropropane toProduce Isomer Mix

The chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out continuously in a glass CSTR stirred reactor.

The reactor consisted of a six-neck glass flask, equipped with amechanical stirrer, a back-cooler, sets of inlets and outlet pipeconnections, a thermos-probe and a 125 W high pressure mercury lamphoused in a quartz glass pipe and immersed into the reactor. Thetemperature in the reactor was maintained using a thermostat. Thepressure in the reactor was atmospheric. The vent gas was linked throughthe back cooler into a HCl scrubber and then into a caustic scrubber.Both scrubbers were regularly analysed with respect to HCl and thechlorine content to monitor the amount of HCl formed as well as anyunreacted chlorine. Chlorine gas was introduced into the reactor via aglass dip pipe with a nozzle outlet and the chlorine was almost totallyconsumed in the reactor.

The liquid feed was introduced in the reactor using a metering pump. Theliquid reaction mixture left the reactor via an overflow pipe and passedinto a collecting tank. Both the liquid feed mixture and chlorine weremonitored by weight. The reaction mixture was analysed by GC.

The temperature in the reactor was about 34° C. There was no metal basedcatalyst employed in the liquid feed. Mean residence time in reactor wasabout 63 minutes. The molar amount of chlorine dosed based on the molesof liquid 1,1,1,3-tetrachloropropane introduced was about 22%. Theresults (in molar percentages) after reaching steady state are shown thefollowing table:

Example No. FeCl₃ = 0 Example 10 Reactor temperature (° C.) 34.1 Meanresidence time (h)  1:03 Chlorine feed rate (mol % towards 1,1,1,3-TCPa)22.0 1,1,1,3-TCPa conversion (mol %) 19.2 Ratio 11133-PCPa:11123 PCPa79.1:20.9 Mol % byproducts:all isomers PCPa  2.41

As shown in this table, the control of conversion of the startingmaterial to the pentachloropropane isomers by limiting the feed ofchlorine resulted in the formation of low levels of impurities, and ahigh selectivity for 1,1,1,3,3-pentachloropropane.

Full details of the composition obtained in this example are providedbelow. As can be seen, the reaction was highly selective towards the twopentachloropropane isomers of interest, 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane. In other words, very low levels ofhexachlorinated propane impurities were produced and no detectablelevels of pentachloropropane isomers other than the isomers of interestwere obtained.

Example No. 10 Compound Amount (wt. %) 113-TCPe 0.004 1333-TeCPe na1133-TeCPe 0.000 1113-TeCPa 77.857  1123-TeCPe na 11133-PCPa 17.018 11123-PCPa 4.490 111333-HCPa 0.280 111233-HCPa 0.194 111223-HCPa 0.124

Example 11 Influence of Catalyst and Temperature

The chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out continuously in a glass CSTR stirred reactor.

The reactor consisted of a six-neck glass flask, equipped with amechanical stirrer, a back-cooler, sets of inlets and outlet pipeconnections, a thermos-probe and 125 W high pressure mercury lamp housedin a quartz glass pipe and immersed into the reactor. The temperature inthe reactor was maintained using a thermostat. The pressure in thereactor was atmospheric. The vent gas was linked through the back coolerinto a HCl scrubber and then into a caustic scrubber. Both scrubberswere regularly analysed with respect to HCl and the chlorine content tomonitor the amount of HCl formed as well as any unreacted chlorine.Chlorine gas was introduced into the reactor via a glass dip pipe with anozzle outlet and the chlorine was almost totally consumed in thereactor.

The liquid feed was introduced in the reactor using a metering pump. Theliquid reaction mixture left the reactor via an overflow pipe and passedinto a collecting tank. Both the liquid feed mixture and chlorine weremonitored by weight. A defined amount of hydrochloric acid was addedinto the reaction mixture collecting tank in order to de-activate themetal-based catalyst. Both the liquid feed mixture and chlorine weremonitored by weight. The reaction mixture was analysed by GC.

The liquid feed was initially dried by CaCl₂ and, after filtration,doped by a defined amount of the metallic catalyst (anhydrous FeCl₃).This liquid feed was then held under a dry nitrogen atmosphere in orderto prevent contamination by atmospheric moisture. The content ofmoisture in the liquid feed was about 12-46 ppmw (trial to trial). Thecontent of 1,1,1,3-tetrachloropropane in the feed was more than 99.9%.

For the first trial, a range of temperatures were employed, namely about40° C., 55° C., 90° C., 105° C. respectively. The amount of anhydrousFeCl₃ in the liquid feed was 12.5 ppmw. Mean residence time in reactorwas about 30 minutes. The molar amount of chlorine dosed based on themoles of liquid 1,1,1,3-tetrachloropropane introduced was about 20%. Theresults after reaching steady state are shown the following table (allratios in molar percent).

Example No. 11.1 11.2 11.2 11.4 Reactor temperature 41.2 84.7 90.1105.1  (° C.) Mean residence time (h)  0:32  0:32  0:31  0:31 Chlorinefeed rate (mol 19.7 19.7 19.4 19.8 % towards 1,1,1,3-TCPa) 1,1,1,3-TCPaconversion 17.2 17.5 17.3 20.7 (mol %) Ratio 11133-PCPa:11123 78.9:21.170.8:29.2 64.1:35.9 17.8:82.2 PCPa % byproducts:all  2.28  2.97  3.25 3.61 isomers PCPa

As can be seen, isomeric selectivity can be influenced by temperaturecontrol. Again, by minimising the conversion of the starting material tothe isomers of interest (through control of the amount of chlorineprovided), this provides control over the levels of impurities that areformed.

The following table illustrates the full compositions obtained from theruns in this example. As can be seen, advantageously, very low levels ofhexachlorinated propanes were obtained. Further, no pentachloropropaneisomers other than the isomers of interest (1,1,1,3,3-pentachloropropaneand 1,1,1,2,3-pentachloropropane) were obtained. Thus, a very highselectivity towards those isomers was advantageously achieved.

Example No. 11.1 11.2 11.3 11.4 Compound Amount (wt. %) 113-TCPe 0.0000.055 0.125 2.502 1333-TeCPe 0.002 0.002 0.002 0.008 1133-TeCPe 0.0000.006 0.016 0.138 1113-TeCPa 80.078 79.796 79.981 77.118 1123-TeCPe na0.017 0.024 0.051 11133-PCPa 15.282 13.764 12.281 3.466 11123-PCPa 4.0885.690 6.871 15.985 111333-HCPa 0.214 0.210 0.170 0.021 111233-HCPa 0.1630.300 0.376 0.568 111223-HCPa 0.108 0.106 0.112 0.054

Example 12 Influence of Conversion of Starting Material and ChlorineFeed on Byproduct Formation

Chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out according to Example 10, but with an increased amount ofchlorine, to increase the conversion of 1,1,1,3-tetrachloropropane. Themolar amount of chlorine dosed based on the moles of1,1,1,3-tetrachloropropane was about 40%. The results after reachingsteady state are shown in the following table (all ratios in molarpercent).

Example No. 12.1 12.2 12.3 12.4 Reactor temperature 80.5 84.9 89.8 94.9(° C.) Mean residence time (h)  0:30  0:30  0:30  0:31 Chlorine feedrate (mol 38.8 38.8 39.4 39.4 % towards 1,1,1,3-TCPa) 1,1,1,3-TCPaconversion 33.5 33.9 34.9 33.3 (mol %) Ratio 11133-PCPa:11123 78.1:21.975.1:24.9 70.6:29.4 64.7:35.3 PCPa % byproducts:all  6.23  6.69  7.19 7.60 isomers PCPa

It can be seen that, in comparison to Example 10, the amount of formedbyproducts, e.g. 111333-HCPa, is higher when using a greater molar ratioof chlorine 1,1,1,3-TCPa in the feed to the reactor.

The following table illustrates the full compositions obtained from theruns in this example. As can be seen, advantageously, very low levels ofhexachlorinated propanes were obtained. Further, no pentachloropropaneisomers other than the isomers of interest (1,1,1,3,3-pentachloropropaneand 1,1,1,2,3-pentachloropropane) were obtained. Thus, a very highselectivity towards those isomers was advantageously achieved.

Example No. 12.1 12.2 12.3 12.4 Compound Amount (wt. %) 113-TCPe 0.0120.021 0.046 0.020 1333-TeCPe na na na na 1133-TeCPe 0.005 0.006 0.0100.012 1113-TeCPa 62.312  61.896  60.826  62.476  1123-TeCPe na na na0.035 11133-PCPa 27.418  26.510  25.484  22.307  11123-PCPa 7.685 8.79510.587  12.147  111333-HCPa 1.055 1.042 0.953 0.754 111233-HCPa 0.9491.112 1.384 1.551 111223-HCPa 0.471 0.495 0.557 0.551

Example 13 Influence of Conversion of 1,1,1,3-Tetrachloropropane andResidence Time

Chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out according to Example 10. However, an increased amount ofchlorine was introduced in order to increase the conversion of feedstock1,1,1,3-tetrachloropropane. The molar amount of chlorine dosed based onthe moles of 1,1,1,3-tetrachloropropane was about 40%. The meanresidence time was about 54 minutes. The results after reaching steadystate are shown the following table (all ratios in molar percent).

Example No. 13.1 13.2 13.3 13.4 Reactor temperature 80.2 85.0 90.1 94.8(° C.) Mean residence time (h)  0:54  0:54  0:54  0:55 Chlorine feedrate (mol 39.4 39.3 39.1 40.6 % towards 1,1,1,3-TCPa) 1,1,1,3-TCPaconversion 34.5 34.8 34.9 36.3 (mol %) Ratio 11133-PCPa:11123 73.6:26.467.6:32.4 54.3:45.7 34.4:65.6 PCPa % byproducts:all  6.87  7.35  7.88 7.39 isomers PCPa

In comparison to the results obtained in Examples 10 and 11, the amountof byproducts formed is greater when conversion of the1,1,1,3-tetrachloropropane starting material to the isomers of interestis increased and when a higher amount of chlorine is fed into thesystem. As can also be seen, the selectivity towards1,1,1,2,3-pentachloropropane is influenced by residence time.

The following table illustrates the full compositions obtained from theruns in this example. As can be seen, advantageously, low levels ofhexachlorinated propanes were obtained. Further, no pentachloropropaneisomers other than the isomers of interest (1,1,1,3,3-pentachloropropaneand 1,1,1,2,3-pentachloropropane) were obtained. Thus, a very highselectivity towards those isomers was advantageously achieved.

Example No. 13.1 13.2 13.3 13.4 Compound Amount (wt. %) 113-TCPe 0.0290.061 0.230 1.313 1333-TeCPe na 0.000 0.001 0.004 1133-TeCPe 0.006 0.0120.029 0.124 1113-TeCPa 61.243 60.912 60.859 59.646 1123-TeCPe 0.0170.023 0.036 0.053 11133-PCPa 26.372 24.297 19.348 12.302 11123-PCPa9.473 11.655 16.270 23.473 111333-HCPa 1.007 0.882 0.570 0.301111233-HCPa 1.208 1.470 1.901 2.079 111223-HCPa 0.534 0.551 0.610 0.490

Example 14 Influence of Increased Amount of Catalyst

Chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out according to Example 10, but with increased amount ofthe catalyst FeCl₃ in the amount of 50 ppmw into the liquid feedstock.The results after reaching steady state are shown the following table(all ratios in molar percent).

Example No. 14.1 14.2 14.3 14.4 Reactor temperature 60.2 70.0 80.0 84.8(° C.) Mean residence time (h)  0:32  0:32  0:32  0:33 Chlorine feedrate (mol 19.3 19.2 19.3 19.8 % towards 1,1,1,3-TCPa) 1,1,1,3-TCPaconversion 17.2 17.2 17.3 19.2 (mol %) Ratio 11133-PCPa:11123 75.5:24.569.6:30.4 47.9:52.1 33.2:66.8 PCPa % byproducts:all  2.46  2.83  3.28 3.46 isomers PCPa

In comparison to Example 10, it can be seen that the increased amount ofcatalyst used permits chlorination to proceed at lower reactiontemperature, without any significant change in isomeric selectivity.

The following table illustrates the full compositions obtained from theruns in this example. As can be seen, advantageously, very low levels ofhexachlorinated propanes were obtained. Further, no pentachloropropaneisomers other than the isomers of interest (1,1,1,3,3-pentachloropropaneand 1,1,1,2,3-pentachloropropane) were obtained. Thus, a very highselectivity towards those isomers was advantageously achieved.

Example No. 14.1 14.2 14.3 14.4 Compound Amount (wt. %) 113-TCPe 0.0000.042 0.332 1.955 1333-TeCPe na na 0.002 0.008 1133-TeCPe 0.002 0.0050.021 0.094 1113-TeCPa 80.118  80.097  80.068 78.615 1123-TeCPe na na0.008 0.023 11133-PCPa 14.568  13.349  9.020 6.143 11123-PCPa 4.7185.837 9.822 12.380 111333-HCPa 0.210 0.189 0.095 0.059 111233-HCPa 0.2060.287 0.455 0.479 111223-HCPa 0.117 0.136 0.127 0.092

Example 15 Continuous Chlorination Zones Operated in Sequence

Chlorination of 1,1,1,3-tetrachloropropane to produce a mixturecomprising 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropanewas carried out continuously in a reactor according to the procedure setout above in Example 10. Chlorination of the 1,1,1,3-tetrachloropropanewas carried out in two CSTR reactors operated in sequence. The reactionmixture from the first CSTR was collected and then used as a liquidfeedstock for the second CSTR. The total amount of 20 mol % of chlorinewas added together in two steps. The results after reaching steady stateare shown the following table (all ratios in molar percent).

Example No. 15.1 15.2 Cascade step 1 2 Reactor temperature (° C.) 35 34Mean residence time (h)  1:01  1:00 Chlorine feed rate (mol % towards1,1,1,3-TCPa) 10.3 11.1 1,1,1,3-TCPa conversion (mol %) 9.4 19.5 Ratio11133-PCPa:11123 PCPa 79.2:20.8 79.1:20.9 % byproducts:all isomers PCPa0.90 1.75

As can be seen by comparing these results from those obtained in Example10, conducting the chlorination reaction in two chlorination zonesoperated in sequence produces less by-products while achieving the samedegree of conversion.

Example No. 15.1 15.2 Compound Amount (wt. %) 113-TCPe 0.004 0.0091333-TeCPe na na 1133-TeCPe 0.001 0.001 1113-TeCPa 89.054  77.588 1123-TeCPe na na 11133-PCPa 8.596 17.357  11123-PCPa 2.258 4.581111333-HCPa 0.057 0.204 111233-HCPa 0.032 0.141 111223-HCPa 0.024 0.085

1. A process for producing a reaction mixture comprising a plurality ofC₃ chlorinated alkane isomers comprising chlorinating a C₃ chlorinatedalkane starting material in a chlorination zone to produce the pluralityof C₃ chlorinated alkane isomers, the plurality of C₃ chlorinated alkaneisomers each having at least one more chlorine atom than the C₃chlorinated alkane starting material, wherein the concentration of theC₃ chlorinated alkane starting material is controlled such thatconversion of the C₃ chlorinated alkane starting material to theplurality of C₃ chlorinated alkane isomers, represented by the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers in the reaction mixture present in the chlorination zone,does not exceed about 40:60.
 2. The process of claim 1, whereinchlorination of the C₃ chlorinated alkane starting material is carriedout by reacting the starting material with chlorine, the chlorinepreferably having a purity of about 99.5% or higher.
 3. The process ofclaim 2, wherein the chlorine is supplied to the chlorination zonesubstoichiometrically with respect to the C₃ chlorinated startingmaterial.
 4. The process of claim 2, wherein the molecular chlorine issupplied to the chlorination zone in an amount of about 15% to about 35%or about 45% by moles of C₃ chlorinated alkane starting material.
 5. Theprocess of claim 2, wherein the chlorine supplied to the chlorinationzone has an oxygen content of about 100 ppm or less.
 6. The process ofclaim 1, wherein chlorination of the C₃ chlorinated alkane startingmaterial is carried out under exposure to UV and/or visible light and/orin the presence of a Lewis acid catalyst.
 7. The process of claim 6,wherein the Lewis acid is a halide of a transition metal or sulfur. 8.The process of claim 6, wherein the Lewis acid catalyst is a halide(e.g. chloride, bromide, fluoride or iodide) of transition metals suchas iron, aluminium, antimony, lanthanum, tin, titanium, or boron orelements such as sulphur or iodine, for example FeCl₃, AlCl₃, SbCl₅,SnCl₄, TiCl₄, BF₃, SO₂Cl₂ and/or metal triflate.
 9. The process of claim6, wherein the Lewis acid catalyst is present in the reaction mixture inan amount of less than about 100 ppm, less than about 75 ppm, less thanabout 50 ppm, or less than about 25 ppm.
 10. The process of claim 1,wherein the operating temperature of the chlorination zone is betweenabout −30° C. and 200° C.
 11. The process of claim 1, wherein thereaction mixture comprises less than about 25000 ppm of over chlorinatedimpurities.
 12. The process of claim 1, wherein the C₃ chlorinatedalkane starting material includes a trichlorinated terminal carbon atom.13. The process of claim 1, wherein the C₃ chlorinated alkane startingmaterial is 1,1,1,3-tetrachloropropane, 1,2,3-trichloropropane,1,2,2,3-tetrachloropropane 1,1,2,3-tetrachloropropane,1,2,2-trichloropropane, 1,2-dichloropropane or mixtures of1,1,2,2-tetrachloropropane and 1,2,2,3-tetrachloropropane or1,1,2,3-tetrachloropropane and 1,2,2,3-tetrachloropropane, or mixturesthereof.
 14. The process of claim 1, wherein the C₃ chlorinated alkanestarting material comprises less than 20 ppm of vinyl chloride and/orwas produced from a process in which vinyl chloride was not used. 15.The process of claim 1, wherein the plurality of C₃ chlorinated alkaneisomers comprises or consists of two isomers, a first and a secondisomer.
 16. The process of claim 1, wherein, in the plurality of isomersproduced in the chlorination zone, the first isomer is present in agreater amount than the second isomer.
 17. The process of claim 16,wherein the molar ratio of the first and second isomers is controlled byone or more of the following: use of Lewis acid catalyst, exposure ofthe reaction mixture to UV/visible light, residence time of the reactionmixture in the chlorination zone and/or operating temperature within thechlorination zone.
 18. The process of claim 1, wherein the molar ratioof the first isomer:second isomer in the plurality of isomers producedin the chlorination zone is from about 60:40 or about 70:30 to about95:5 or about 98:2.
 19. The process of claim 1, wherein the molar ratioof the first isomer:second isomer in the plurality of isomers producedin the chlorination zone is 40:60 to about 60:40.
 20. The process ofclaim 1, wherein the plurality of C₃ chlorinated alkane isomers consistof: 1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane,1,1,1,2,3-pentachloropropane and 1,1,2,2,3-pentachloropropane, or1,1,2,2,3-pentachloropropane and 1,1,1,2,2-pentachloropropane.
 21. Theprocess of claim 15, wherein the plurality of C₃ chlorinated alkaneisomers consist of 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane and 1,1,1,3,3-pentachloropropane is thefirst isomer and 1,1,1,2,3-pentachloropropane is the second isomer. 22.The process of claim 21, wherein the molar ratio of the firstisomer:second isomer is 70:30 to 99:1.
 23. The process of claim 21,wherein Lewis acid catalyst is not supplied to the chlorination zone andthe chlorination zone is exposed to UV/visible light.
 24. The process ofclaim 15, wherein the plurality of C₃ chlorinated alkane isomers consistof 1,1,1,2,3-pentachloropropane and 1,1,1,3,3-pentachloropropane and1,1,1,2,3-pentachloropropane is the first isomer and1,1,1,3,3-pentachloropropane is the second isomer.
 25. The process ofclaim 24, wherein the molar ratio of the first isomer:second isomer is70:30 to 99:1.
 26. The process of claim 25, wherein Lewis acid catalystis supplied to the chlorination zone and the chlorination zone isoptionally exposed to UV/visible light, the Lewis acid catalystoptionally being formed in situ, for example by adding transition metalto the chlorination zone.
 27. The process of claim 1, wherein thechlorine content of the reaction mixture extracted from the chlorinationzone is about 0.05% or less.
 28. The process of claim 1, furthercomprising one or more distillation steps on the reaction mixture, saidone or more distillation steps being carried out using distillationapparatus in direct communication with the chlorination zone and/orbeing carried out on reaction mixture extracted from the chlorinationzone using distillation apparatus remote from the chlorination zone. 29.The process of claim 28, wherein said one or more distillation stepsresult in a plurality of C₃ chlorinated alkane isomer stream beingobtained which is rich in or consists of the plurality of C₃ chlorinatedalkane isomers.
 30. The process of claim 29, wherein said one or moredistillation steps result in one or more of the following streams beingobtained: one or more unreacted C₃ chlorinated alkane starting materialstreams which is rich in or consists of the C₃ chlorinated alkanestarting material, one or more single isomer streams rich in orconsisting of one of the C₃ chlorinated alkane isomers, and one or moredistillation residue streams rich in or consisting of under chlorinatedimpurities, over chlorinated impurities and/or impurities having adifferent number of carbon atoms to the isomers.
 31. The process ofclaim 30, wherein a single isomer stream is obtained via distillationwhich is rich in or consists of the second isomer, resulting in a changein the molar ratio of first and second isomers in the plurality of C₃chlorinated alkane isomers, namely a reduction in the proportion of thesecond isomer and an increase in the proportion of the first isomer. 32.The process of claim 31, wherein the increase in the proportion of thefirst isomer is by at least about 5%.
 33. The process of claim 31,wherein the increase in the proportion of the first isomer is by atleast about 10%.
 34. The process of claim 28, wherein an unreacted C₃chlorinated alkane starting material stream is obtained via directdistillation using distillation apparatus in communication with thechlorination zone.
 35. The process of claim 28, wherein the plurality ofC₃ chlorinated alkane isomer stream and/or the one or more single isomerstream/s, where obtained, comprise: less than about 10000 ppm, less thanabout 5000 ppm, less than about 2000 ppm, less than about 1000 ppm, lessthan about 500 ppm, less than about 200 ppm, less than about 100 ppm,less than about 50 ppm, less than about 20 ppm, less than about 10 ppmor less than about ppm of under chlorinated impurities, less than about5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less thanabout 500 ppm, less than about 200 ppm, less than about 100 ppm, lessthan about 50 ppm, less than about 20 ppm, less than about 10 ppm orless than about 5 ppm of over chlorinated impurities, less than about5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less thanabout 500 ppm, less than about 200 ppm, less than about 100 ppm, lessthan about 50 ppm, less than about 20 ppm, less than about 10 ppm orless than about 5 ppm of chlorinated alkene compounds, less than about1000 ppm, less than about 500 ppm, less than about 200 ppm, less thanabout 100 ppm, less than about 50 ppm, less than about 20 ppm, less thanabout 10 ppm or less than about 5 ppm of compounds having a differentnumber of carbon atoms than the isomers, less than about 1000 ppm, lessthan about 500 ppm, less than about 200 ppm, less than about 100 ppm,less than about 50 ppm, less than about 20 ppm, less than about 10 ppmless than about 5 ppm, or less than about 2 ppm of oxygenated organicimpurities, less than about 500 ppm, less than about 200 ppm, less thanabout 100 ppm, less than about 50 ppm, less than about 20 ppm, less thanabout 10 ppm or less than about 5 ppm metal, and/or less than about 100ppm, less than about 50 ppm, less than about 20 ppm, less than about ppmor less than about 5 ppm water.
 36. The process of claim 1, wherein thereaction mixture is extracted from the chlorination zone and subjectedto subsequent chlorination steps in 1, 2, 3, or 4 sequentially arrangeddownstream chlorination zones, wherein the molar ratio of the C₃chlorinated alkane starting material:C₃ chlorinated alkane isomers inthe reaction mixture present in any of the downstream chlorination zonesdoes not exceed about 40:60.
 37. The process of claim 28, furthercomprising the steps of feeding a mixture into an aqueous treatmentzone, contacting the mixture with an aqueous medium and extracting atreated mixture comprising reduced levels of oxygenated compounds, themixture being reaction mixture extracted from the chlorination zone, aplurality of C₃ chlorinated alkane isomer stream obtained viadistillation from the reaction mixture or a partially distilled reactionmixture, namely reaction mixture extracted from the chlorination zonefrom which one or more of an unreacted C₃ chlorinated alkane startingmaterial stream, one or more single isomer streams and/or one or moredistillation residue streams has already been obtained via distillation.38. A process for treating a mixture comprising at least two C₃chlorinated alkane isomers and oxygenated organic compounds comprisingfeeding the mixture into an aqueous treatment zone, contacting themixture with an aqueous medium and extracting a treated mixturecomprising reduced levels of oxygenated compounds.
 39. The process ofclaim 37, wherein the treated mixture comprises oxygenated organiccompounds in amounts of about 1000 ppm or less, about 500 ppm or less,about 200 ppm or less, about 100 ppm or less, about 50 ppm or less, orabout 10 ppm or less.
 40. The process of claim 37, wherein the aqueoustreatment steps precede none, one, some or all of the distillationstep/s.
 41. The process of claim 28, wherein the chlorination zone iscomprised within a continuous stirred tank reactor, a circulation orloop reactor, and/or tubular reactor, or optionally a plurality the sameor different types of said reactors arranged in a cascade.
 42. Theprocess of claim 41, wherein the chlorination zone is comprised in acontinuous stirred tank reactor, chlorination is promoted by UV and/orvisible light and the molar ratio of the C₃ chlorinated alkane startingmaterial:C₃ chlorinated alkane isomers in the reaction mixture does notexceed about 60:40.
 43. The process of claim 41, wherein the molar ratioof the C₃ chlorinated alkane starting material:C₃ chlorinated alkaneisomers in the reaction mixture is from 95:5 to 75:25 and optionally,the chlorination zone is comprised in a circulation or loop reactorconfigured such that the reaction mixture is in communication withdistillation apparatus to enable the reaction mixture to be subject todirect distillation, the operating temperature of the chlorination zonepreferably does not exceed about 120° C.
 44. The process of claim 41,wherein the chlorination zone is comprised in a falling film tubularphotoreactor and the molar ratio of the C₃ chlorinated alkane startingmaterial:C₃ chlorinated alkane isomers in the reaction mixture does notexceed about 40:60.
 45. The process of claim 1, wherein chlorinationand/or distillation is conducted in the absence of oxygen.
 46. A processfor producing a C₃ chlorinated alkene comprising providing a mixturecomprising a plurality of C₃ chlorinated alkane isomers, the boilingpoint of at least two of the plurality of C₃ chlorinated alkane isomersdiffering by ≦15° C., comprising subjecting the mixture to a selectivedehydrochlorination step in a dehydrochlorination zone in which one ofthe at least two C₃ chlorinated alkane isomers, a first C₃ chlorinatedalkane isomer, is selectively converted to a respective first C₃chlorinated alkene without the substantial dehydrochlorination of any ofthe other of the plurality of C₃ chlorinated alkane isomers.
 47. Theprocess of claim 46, wherein dehydrochlorination is conducted in theliquid phase and the operating temperature of the dehydrochlorinationzone is optionally from about 50° C., about 70° C. or about 80° C. toabout 120° C. or about 150° C.
 48. The process of claim 46, wherein themixture comprising a plurality of C₃ chlorinated alkane isomers isobtainable from the processes comprising chlorinating a C₃ chlorinatedalkane starting material in a chlorination zone to produce the pluralityof C₃ chlorinated alkane isomers, the plurality of C₃ chlorinated alkaneisomers each having at least one more chlorine atom than the C₃chlorinated alkane starting material, wherein the concentration of theC₃ chlorinated alkane starting material is controlled such thatconversion of the C₃ chlorinated alkane starting material to theplurality of C₃ chlorinated alkane isomers, represented by the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers in the reaction mixture present in the chlorination zone,does not exceed about 40:60.
 49. The process of claim 48, wherein themixture comprising a plurality of C₃ chlorinated alkane isomers is theplurality of C₃ chlorinated alkane isomer stream obtained from theprocesses. wherein the molar ratio of the first and second isomers iscontrolled by one or more of the following: use of Lewis acid catalyst,exposure of the reaction mixture to UV/visible light, residence time ofthe reaction mixture in the chlorination zone and/or operatingtemperature within the chlorination zone.
 50. The process of claim 46,wherein the mixture comprising a plurality of C₃ chlorinated alkaneisomers has a purity of about 95% or higher, about 97% or higher, about99% or higher, about 99.5% or higher, about 99.7% or higher, about 99.8%or higher or about 99.9% or higher, and further comprises: less thanabout 10000 ppm, less than about 5000 ppm, less than about 2000 ppm,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, less than about 100 ppm, less than about 50 ppm, less than about 20ppm, less than about 10 ppm or less than about ppm of under chlorinatedimpurities, less than about 5000 ppm, less than about 2000 ppm, lessthan about 1000 ppm, less than about 500 ppm, less than about 200 ppm,less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm of over chlorinatedimpurities, less than about 5000 ppm, less than about 2000 ppm, lessthan about 1000 ppm, less than about 500 ppm, less than about 200 ppm,less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm of chlorinated alkenecompounds, less than about 1000 ppm, less than about 500 ppm, less thanabout 200 ppm, less than about 100 ppm, less than about 50 ppm, lessthan about 20 ppm, less than about 10 ppm or less than about 5 ppm ofcompounds having a different number of carbon atoms than the isomers,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, less than about 100 ppm, less than about 50 ppm, less than about 20ppm, less than about 10 ppm less than about 5 ppm, or less than about 2ppm of oxygenated organic impurities, less than about 500 ppm, less thanabout 200 ppm, less than about 100 ppm, less than about 50 ppm, lessthan about 20 ppm, less than about 10 ppm or less than about 5 ppmmetal, and/or less than about 100 ppm, less than about 50 ppm, less thanabout 20 ppm, less than about ppm or less than about 5 ppm water. 51.The process of claim 46, wherein a metal-containing catalyst is used inthe selective dehydrochlorination step.
 52. The process of claim 51,wherein the catalyst comprises elemental iron and/or an iron salt suchas FeCl₃.
 53. The process of claim 46, wherein the dehydrochlorinationzone is free of alkaline hydroxide.
 54. The process of claim 46, whereindehydrochlorination is conducted in a series of dehydrochlorinationzones that may be comprised in one or more reactors, said series ofdehydrochlorination zones operated as a cascade.
 55. The process ofclaim 46, wherein the reaction mixture produced in thedehydrochlorination zone comprises the plurality of C₃ chlorinatedalkane isomers having a reduced proportion of the first C₃ chlorinatedalkane isomer, the first C₃ chlorinated alkene, optionally catalyst andoptionally impurities.
 56. The process of claim 46, wherein a streamrich in or consisting of the first C₃ chlorinated alkene is obtainedfrom the reaction mixture via distillation.
 57. The process of claim 56,wherein a single isomer stream which is rich in or consisting of thefirst C₃ chlorinated alkane isomer is obtained from the reaction mixturevia distillation.
 58. The process of claim 56, wherein the plurality ofC₃ chlorinated alkane isomers comprises a second C₃ chlorinated alkaneisomer, and a single isomer stream which is rich in or consisting of thesecond C₃ chlorinated alkane isomer is obtained from the reactionmixture via distillation.
 59. The process of claim 57, wherein thesingle isomer stream/s and/or the stream rich in or consisting of thefirst C₃ chlorinated alkene are obtained via the same or differentdistillation steps.
 60. The process of claim 56, wherein distillation iscarried out using distillation apparatus in direct communication withthe dehydrochlorination zone and/or is carried out on reaction mixtureextracted from the dehydrochlorination zone using distillation apparatusremote from the chlorination zone.
 61. The process of claim 56, whereinthe reaction mixture is subjected to one or more additional treatmentsteps, wherein at least one of the additional treatment steps isoptionally carried out prior to the reaction mixture being subjected todistillation.
 62. The process of claim 61, wherein the one or moreadditional treatment steps comprises contacting the reaction mixturewith an aqueous medium in an aqueous treatment zone to form a biphasicmixture, and extracting the organic phase from that biphasic mixture.63. The process of claim 62, wherein the pH of the mixture/biphasicmixture in the aqueous treatment zone, following the addition of acid,is about 4 or lower.
 64. The process of claim 62, wherein themixture/biphasic mixture is contacted with a haloalkane extractionagent.
 65. The process of claim 61, wherein the first C₃ chlorinatedalkene is extracted from the organic phase.
 66. The process of claim 46,wherein some or all surfaces of the apparatus in which the process iscarried out with which any chlorinated alkene-containing mixture willcontact during use of that apparatus have an iron content of about 20%or less, about 10% or less or about 5% or less, and/or are formed fromnon-metallic materials, for example enamel, glass, impregnated graphite(e.g. impregnated with phenolic resin), silicium carbide and/or plasticsmaterials such as polytetrafluoroethylene, perfluoroalkoxy and/orpolyvinylidene fluoride.
 67. The process of claim 46, wherein theplurality of C₃ chlorinated alkane isomers consist of:1,1,1,2,3-pentachloropropane and 1,1,1,3,3-pentachloropropane,1,1,1,2,3-pentachloropropane and 1,1,2,2,3-pentachloropropane, or1,1,2,2,3-pentachloropropane and 1,1,1,2,2-pentachloropropane.
 68. Theprocess of claim 46, wherein: the plurality of C₃ chlorinated alkaneisomers consist of 1,1,1,2,3-pentachloropropane and1,1,1,3,3-pentachloropropane and 1,1,1,3,3-pentachloropropane is thefirst C₃ chlorinated alkane isomer and 1,1,1,2,3-pentachloropropane isthe second C₃ chlorinated alkane isomer, the plurality of C₃ chlorinatedalkane isomers consist of 1,1,1,2,3-pentachloropropane and1,1,2,2,3-pentachloropropane and 1,1,1,2,3-pentachloropropane is thefirst C₃ chlorinated alkane isomer and 1,1,2,2,3-pentachloropropane isthe second chlorinated alkane isomer, or the plurality of C₃ chlorinatedalkane isomers consist of 1,1,2,2,3-pentachloropropane and1,1,1,2,2-pentachloropropane and 1,1,1,2,2-pentachloropropane is thefirst C₃ chlorinated alkane isomer and 1,1,2,2,3-pentachloropropane isthe second chlorinated alkane isomer.
 69. A process comprising:preparing a reaction mixture comprising a plurality of C₃ chlorinatedalkane isomers comprising chlorinating a C₃ chlorinated alkane startingmaterial in a chlorination zone to produce the plurality of C₃chlorinated alkane isomers, the plurality of C₃ chlorinated alkaneisomers each having at least one more chlorine atom than the C₃chlorinated alkane starting material, wherein the concentration of theC₃ chlorinated alkane starting material is controlled such thatconversion of the C₃ chlorinated alkane starting material to theplurality of C₃ chlorinated alkane isomers, represented by the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers present in the chlorination zone does not exceed about40:60, subjecting the reaction mixture to one or more first distillationsteps to produce a plurality of C₃ chlorinated alkane isomer stream, oneor more single C₃ chlorinated alkane isomer streams and optionally a C₃chlorinated alkane starting material stream, subjecting the plurality ofC₃ chlorinated alkane isomers stream to a selective dehydrochlorinationstep in which one of the C₃ chlorinated alkane isomers, the first C₃chlorinated alkane isomer, is converted to a respective first C₃chlorinated alkene without the substantial dehydrochlorination of any ofthe other of the plurality of C₃ chlorinated alkane isomers, andobtaining a stream rich in or consisting of the first C₃ chlorinatedalkene from the mixture prepared in the dehydrochlorination step. 70.The process of claim 46, wherein the first C₃ chlorinated alkene is1,1,3,3-tetrachloropropene.
 71. The process of claim 1, wherein thechlorination zone and/or the dehydrochlorination zone are in continuousoperation.
 72. A process for preparing a hydrofluoroolefin orhydrochlorofluoroolefin, comprising providing a mixture comprising aplurality of C₃ chlorinated alkane isomers, the boiling point of atleast two of the plurality of C₃ chlorinated alkane isomers differing by≦15° C., comprising subjecting the mixture to a selectivedehydrochlorination step in a dehydrochlorination zone in which one ofthe at least two C₃ chlorinated alkane isomers, a first C₃ chlorinatedalkane isomer, is selectively converted to a respective first C₃chlorinated alkene without the substantial dehydrochlorination of any ofthe other of the plurality of C₃ chlorinated alkane isomers, andconverting the C₃ chlorinated alkene to the hydrofluoroolefin orhydrochlorofluoroolefin.
 73. The process of claim 72, wherein the C₃chlorinated alkene is 1,1,3,3-tetrachloropropene and thehydrofluoroolefin is 1,3,3,3-tetrafluoropropene or2,3,3,3-tetrafluoropropene or the hydrochlorofluoroolefin is1-chloro-3,3,3-trifluoropropene.
 74. The process of claim 72, whereinthe conversion of the C₃ chlorinated alkene to the hydrofluoroolefin orthe hydrochlorofluoroolefin is conducted in a hydrofluorination plant.75. A composition comprising a plurality of C₃ chlorinated alkaneisomers at a purity of about 95% or higher, about 97% or higher, about99% or higher, about 99.5% or higher, about 99.7% or higher, about 99.8%or higher or about 99.9% or higher, further comprising: less than about10000 ppm, less than about 5000 ppm, less than about 2000 ppm, less thanabout 1000 ppm, less than about 500 ppm, less than about 200 ppm, lessthan about 100 ppm, less than about 50 ppm, less than about 20 ppm, lessthan about 10 ppm or less than about ppm of under chlorinatedimpurities, less than about 5000 ppm, less than about 2000 ppm, lessthan about 1000 ppm, less than about 500 ppm, less than about 200 ppm,less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm of over chlorinatedimpurities, less than about 5000 ppm, less than about 2000 ppm, lessthan about 1000 ppm, less than about 500 ppm, less than about 200 ppm,less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm of chlorinated alkenecompounds, less than about 1000 ppm, less than about 500 ppm, less thanabout 200 ppm, less than about 100 ppm, less than about 50 ppm, lessthan about 20 ppm, less than about 100 ppm or less than about 5 ppm ofcompounds having a different number of carbon atoms than the isomers,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, less than about 100 ppm, less than about 50 ppm, less than about 20ppm, less than about 100 ppm less than about 5 ppm, or less than about 2ppm of oxygenated organic impurities, less than about 500 ppm, less thanabout 200 ppm, less than about 100 ppm, less than about 50 ppm, lessthan about 20 ppm, less than about 10 ppm or less than about 5 ppmmetal, and/or less than about 100 ppm, less than about 50 ppm, less thanabout 20 ppm, less than about ppm or less than about 5 ppm water. 76.The composition of claim 75, wherein the composition is obtainable fromthe process comprising chlorinating a C₃ chlorinated alkane startingmaterial in a chlorination zone to produce the plurality of C₃chlorinated alkane isomers, the plurality of C₃ chlorinated alkaneisomers each having at least one more chlorine atom than the C₃chlorinated alkane starting material, wherein the concentration of theC₃ chlorinated alkane starting material is controlled such thatconversion of the C₃ chlorinated alkane starting material to theplurality of C₃ chlorinated alkane isomers, represented by the molarratio of the C₃ chlorinated alkane starting material:C₃ chlorinatedalkane isomers in the reaction mixture present in the chlorination zone,does not exceed about 40:60.
 77. The composition of claim 75, whereinthe plurality of C₃ chlorinated alkane isomers consist of1,1,1,3,3-pentachloropropane and 1,1,1,2,3-pentachloropropane.
 78. Thecomposition of claim 77, wherein the molar ratio of1,1,1,3,3-pentachloropropane:1,1,1,2,3-pentachloropropane is from about85:15, or about 90:10 to about 95:5 or about 98:2.
 79. The use of thecomposition of claim 75 as a feedstock for a selectivedehydrochlorination process: a) in which one of the two C₃ chlorinatedalkane isomers, a first C₃ chlorinated alkane isomer, is selectivelyconverted to a respective first C₃ chlorinated alkene without thesubstantial dehydrochlorination of any of the other of the plurality ofC₃ chlorinated alkane isomers, or b) in a mixture comprising a pluralityof C₃ chlorinated alkane isomers, the boiling point of at least two ofthe plurality of C₃ chlorinated alkane isomers differing by ≦15° C.,comprising subjecting the mixture to a selective dehydrochlorinationstep in a dehydrochlorination zone in which one of the at least two C₃chlorinated alkane isomers, a first C₃ chlorinated alkane isomer, isselectively converted to a respective first C₃ chlorinated alkenewithout the substantial dehydrochlorination of any of the other of theplurality of C₃ chlorinated alkane isomers.
 80. The use of thecomposition of claim 75 as a feedstock in the production ofhydrofluoroolefin or hydrochlorofluoroolefin compounds.
 81. The use ofclaim 80, wherein the hydrofluoroolefin compounds are1,3,3,3-tetrafluoropropene or 2,3,3,3-tetrafluoropropene and thehydrochlorofluoroolefin is 1-chloro-3,3,3-trifluoropropene.
 82. Acomposition comprising a C₃ chlorinated alkane selected from1,1,1,2,3-pentachloropropane and 1,1,1,3,3-pentachloropropane and a C₃chlorinated alkene selected from 1,1,2,3-tetrachloro-1-propene,1,1,3,3-tetrachloro-1-propene, and 1,3,3,3 tetrachloro-1-propene, the C₃chlorinated alkane and the C₃ chlorinated alkene together having apurity of about 95% or higher, about 97% or higher, about 99% or higher,about 99.5% or higher, about 99.7% or higher, about 99.8% or higher orabout 99.9%, the composition further comprising: less than about 10000ppm, less than about 5000 ppm, less than about 2000 ppm, less than about1000 ppm, less than about 500 ppm, less than about 200 ppm, less thanabout 100 ppm, less than about 50 ppm, less than about 20 ppm, less thanabout 10 ppm or less than about ppm of C₃ chlorinated alkane compoundscomprising less chlorine atoms than the C₃ chlorinated alkane, less thanabout 5000 ppm, less than about 2000 ppm, less than about 1000 ppm, lessthan about 500 ppm, less than about 200 ppm, less than about 100 ppm,less than about 50 ppm, less than about 20 ppm, less than about 10 ppmor less than about 5 ppm of C₃ chlorinated alkane compounds comprisingmore chlorine atoms than the C₃ chlorinated alkane, less than about 5000ppm, less than about 2000 ppm, less than about 1000 ppm, less than about500 ppm, less than about 200 ppm, less than about 100 ppm, less thanabout 50 ppm, less than about 20 ppm, less than about 10 ppm or lessthan about 5 ppm of chlorinated alkene compounds other than the C₃chlorinated alkene compound, less than about 10000 ppm, less than about5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less thanabout 500 ppm, less than about 200 ppm, less than about 100 ppm, lessthan about 50 ppm, less than about 20 ppm, less than about 10 ppm orless than about ppm of compounds having a different number of carbonatoms than the C₃ chlorinated alkane compound, less than about 1000 ppm,less than about 500 ppm, less than about 200 ppm, less than about 100ppm, less than about 50 ppm, less than about 20 ppm, less than about 10ppm less than about 5 ppm, or less than about 2 ppm of oxygenatedorganic impurities, less than about 500 ppm, less than about 200 ppm,less than about 100 ppm, less than about 50 ppm, less than about 20 ppm,less than about 10 ppm or less than about 5 ppm metal, and/or less thanabout 100 ppm, less than about 50 ppm, less than about 20 ppm, less thanabout ppm or less than about 5 ppm water.
 83. The composition of claim82, wherein the composition is obtainable from the process comprisingproviding a mixture comprising a plurality of C₃ chlorinated alkaneisomers, the boiling point of at least two of the plurality of C₃chlorinated alkane isomers differing by ≦15° C., comprising subjectingthe mixture to a selective dehydrochlorination step in adehydrochlorination zone in which one of the at least two C₃ chlorinatedalkane isomers, a first C₃ chlorinated alkane isomer, is selectivelyconverted to a respective first C₃ chlorinated alkene without thesubstantial dehydrochlorination of any of the other of the plurality ofC₃ chlorinated alkane isomers.
 84. The use of the composition of claim82 as a feedstock in the production of a hydrofluoroolefin orhydrochlorofluoroolefin compound.
 85. The use of claim 84, wherein thehydrofluoroolefin compound is 1,3,3,3-tetrafluoropropene or2,3,3,3-tetrafluoropropene or the hydrochlorofluoroolefin is1-chloro-3,3,3-trifluoropropene.